I type much slower on my phone than on a keyboard, but it's clearly still useful.

I have a music recording studio set up at home. I can imagine some scenarios where it might be easier for me to wave my hand for some brief computer interaction than to reposition myself for regular keyboard-typing and mouse-moving.

But, shrug, in any event, I think it's neat to see LeapMotion technology being brought to more applications. Maybe some of them will prove silly, but at least people are trying to figure out how to use it, which is more than I can say for myself thus far...