Video:

I didn't used this functionality with a tablet yet (but I suppose that the author of the video is using one); with a mouse I can say that painting on a layer with a layer style is doable (the response is reasonable fast on a computer with decent spec) when using small/medium brushes.
Edit: I should add that you can't save them (I think ). Soooo, testing purpose only, for now.
Edit 2: OK, they are fast enough with a tablet too.