I apologize in advance, as I'm going to spend a majority of this post explaining concepts in matchups rather than directly answering your question for the most part. Sorry.
In OvO, there's really only one use for rage. It's somewhat useful for a rage -> tower spawn timing attack with an archer follow up. If your opponent plays greedy, it can really devastate them. However, safe archer play dominates the game in all matchups. There's no real way to get around that.
In OvC you can use rage to a lot better effect. Swords can do a lot of work and force out more bombers than your opponent probably wants. I've ended the game a lot of times vs mid-high level chaos players with a 3 minute 4 ragesword timing attack. It's all in how you set up the attack though, because the only time it will be effective is in the window where the chaos player has stopped bomber production in favor of juggerknights, but has few to no juggers on the field. Generally in this time you won't see turrets because of the initial cost of poisondeads+jugger. Beyond that point in the game there is very little use for swords, and you want to transition to almost pure archer/meric. Speartons are likewise unfavorable to buy, as they delay your tech to ninjas and hamper archer count growth.
Speed+PackCrawlers, on the other hand have their place in every matchup. For example, CvO has a pretty significant window (2:20-3:10) where speed crawlers can nearly guarantee tower control if you don't take significant losses in crawler count early. I'll often take this tech path as a punish to very defensive order styles, as it allows for a strong punish to archers with bad spacing, and facilitates the ability to poke onto walls. If an order player does not have Wall/CA set up vs a significant crawler pack they WILL end the game. Without a wall, Tower spawn will tank any CA splash and allow your pack to move on the first goldrow, easily shutting down an order economy.
If it doesn't end the game, but does a moderate amount of damage. It still puts you a ahead. Compared to the standard StraightToPoisonTower builds that you see in high level CvO, you will have more map control and thus more chance to get Passives and manage your eco. Not only this, but it will force out static defense that you otherwise want to avoid making as order, meaning his archer/miner count will be lower compared to a standard game.
You don't want to go above 15 or so crawlers, as the DPS provided will only be noticeable vs a stationary target like the statue, and it further incentivizes a quick mage tech, which you don't want. From the point of the initial tech not ending the game, your follow up is either FastMarrow or Standard play. I like FastMarrow if I know my opponent cannot end the game with a counterpush. It is a good way to counter an unsupported mage, which is the traditional "counter" to Rage or Pack builds. Marrows are also the ultimate tool for attrition vs archer based comps. Together it sets you up for a very tough to challenge late game, with your only real concern being a large ninja switch, which is generally impossible on a stunted economy. However, in the event this tech path does happen you can simply transition to jugger/wing. Wings are surprisingly population effective for the DPS they have in late game. In the supreme end game you'll have to worry about a massive archer clump, but so long as order cannot approach your marrows or medusapool you will be fine going wings.
The other transition from this type of play is just a later switch into a standard composition. At your level, you may not yet know what this means, so I'll describe it here. Standard play in CvO consists of a switch from the early play of crawler/bomber stall to dead/bomber/crawler stall. I personally like to follow up with AtTowerTurrets before first jugger, though there are other top chaos players who prefer the safety of JuggerFirst to punish heavy sword play or quick SpearWall/Meric. Deads are one of the best units in the game for hard DPS. This is not because they do much damage on hit, but their DPM is very high because of their survivability in a straight engagement compared to Eclipsors or Archidons. In addition, their main attack inflicts a low-medium strength poison on-hit for 10 Mana. This might seem like a light mana cost, but it adds up VERY quickly in mid-late game. Often you'll need 4-6 on mana to fuel your deads in addition to creating new units and upgrading. Now, you might be asking why these units would be a good transition from crawler play. This is because deads have equal range to archers, and thus make good siege units on order players who have few to no merics or tanking units, such as swords. Crawlers and miners are fairly cheap, and if you are constantly training miners you will have a very nice steady income growth and bank going into the midgame. This is what makes this type of play so strong, the ability to quickly outproduce the order player and force them into a defensive position. If you follow up the crawler play around the 3:50-4:15 mark with dead poison and your first two deads the order player will have a tougher time justifying going for mage, as they need merics to approach a chaos player who is using deads. This sets you up for an even safer tech into jugger/dead play. Because cralwer/dead/jugger is so much population around the 5:40 mark and beyond, you will accumulate a pretty considerable bank going onto max pop. With this you can essentially do whatever you want vs someone who isn't a top level player. You can just continually attack and pressure back the order player who should already be behind with your economy to outproduce them. So long as you take even or close to even trades you will ALWAYS come out on top, because you have map control AND a better economy. If you take any favorable engagements it usually spells the end for an order player. However, if the engagements you are taking are considerably in favor or will be in favor of the order player, you should immediately disengage and begin teching to marrow/jugger/bomber. The classic mistake of a chaos player in this situation is to max out on mostly deads as their population. If you do this, you will never be able to end the game against a competent order player, as they will simply harass you into oblivion with archers until the point where they can bank a significant amount of ninjas to just kill a chaos army with burst damage. Another classic mistake is to tech to Cgiants when you can't support them. Juggers are almost ALWAYS a better choice to spend banked gold on than chaos giants. Again, to reiterate you follow up the lead from crawler tech timing attack by playing it safe and transitioning to standard tech. Don't linger on it or try to get fancy with marrow/giant, as you WILL lose to a competent order player.
In CvC there are very niche uses for Crawler upgrades, mostly in relation to late game scenarios with mostly medusa based compositions. If you see your opponent going for very early 4OnMana and you can't immediately end the game, you can transition to your own 4OnMana and start banking crawlers. Generally speaking, if your opponent goes for medusa tech from the 3:50-4:30 mark you can just punish it with crawler tech rather than staying on standard dead/jugger as they'll likely end up wearing you down with higher medusa count. Crawlers have enough burst damage and surprise factor that they can often be a good punish even in high level CvC. This is really the only time you should get crawler upgrades in CvC, however, as the only other uses are even more niche punishes than even this one.
By contrast, CvE is the matchup where I'd argue Crawler upgrades are not only usable, but even standard. Banking crawlers after your first turret allows you to not only punish trees that get too close before you have a significant Eclipsor count, but also punish any sort of early V tech. With fires and Blast being the main ways elementals can come back in the matchup, cralwers are a very safe answer, as they necessitate wasting precious water to use blast on them instead of your wings. Not only that, but they're an extremely good gold dump. The matchup is mostly mana based because of the Marrow/Wing comps that are necessary for - and so very good at - killing Tree/Cycloid. Because of that, cralwers are a nice way to wall out elementals ground units as well as way to dump gold in a matchup where juggers and giants are mostly useless, even detrimental at times.
Now, for all these benefits there are clear disadvantages to going for crawler upgrades, which stifles their use in CvO and CvC. They're the second most frail unit in the game, only beating out archers by virtue of passively healing. This means that bombers and archers are excellent answers with proper spacing. It takes very good hitbox knowledge, experience, and quite a bit of luck to be able to perfectly space crawlers against archers. And against bombers, this in even more difficult, as bombers will effectively force you back forever until you answer with your own bombers, stifling the ability to really mass them effectively. In addition, Castle Archer II and Turrets present insurmountable defense against all but the most dedicated crawler spammers. You will never cost effectively win with only crawlers, unless you gimp an archer start or win a very serious early CvC confrontation with them. These factors, as well as the clear benefits of standard play in comparison (safety) prevent widespread use of crawler upgrades.
I hope this helped answer your questions!