That's what I've been figuring, but... will there be a performance difference? I mean, I use a LOT of grass. A stupid amount, really. The level I'm working on isn't even half done and there's 208 grass sprites. I'll eventually put in options to turn off certain effects, probably replacing the individual sprites with static tiled backgrounds, so I guess it's not a huge deal.
But in the same way the particle system is more efficient than you spawning the sprites yourself, is the sine behavior more efficient than manually rotating all the grass (maybe 30-40 on screen at once)?