Holding something slowly builds up spin. Longer you hold faster it spins. Either it builds spin slow enough that it doesn't matter if it gets fast, or it has a max rpm
Lighter rocks spin up faster. Larger ones take time.
Pros:
Rocks that can roll and thus curve intentionally in a direction.
Might help "waterbending" tech.
Cons:
Your held rocks are spinning if you don't release them soon enough. Could cause self damage if not mastered.
Doubled edged, but so is volatile.
(I keep thinking I've already made this post. (or maybe someone else has...my bad if so for making it again (searching on this site is not so easy)))