Looking at the documentation, it says, “Using a smoke cloud as an example, each particle would have a small smoke texture.”
Coincidentally, I want to have big smoke clouds after a projectile hits something. But would this kill the frame rate, especially for mobile devices?
I use plenty of particle effects, even overlapping particle effects, on an iPad. Runs fine. and that’s with a dozen physics objects each in the hundreds of poly-count bouncing around.
I’ve read how mobile graphics cards are especially bad at large overlapping transparent objects. But I haven’t seen a problem with that either (but, again, iPad, not a phone, which I assume is worse.)
As far as I can tell, particle emitters are the same as anything else. Just don’t overdo them (unless nothing else is gong on.)
But, make a test. Add a giant smoke cloud glued in front of the camera, with a cheap gui button to turn it on/off. Add three different emitters to the player, with ugly buttons to toggle them. Add a stupidly large emitter far to the right. See how much the game slows when you walk so it’s in view. Make sure you push it so the frame rate sinks, when enough are turned on. Then you’ll know how much you can add.