i don't really know but i hardly ever use them so why do everyone else
P.S i don't really know how to use them

It enables people to use filters.
Can also be used to make loops.
Makes editing easier.
It makes things a little bit more organized.

Yeah those are the ones I can think of atm.

they also help in adding tons of great effects
used if you want to use something over and over again without redrawing it (stick heads)

you pretty much simplified what he said.

Quote from Smile

It enables people to use filters.
Can also be used to make loops.