It seems this type of technology is reinvented every decade or so but it never really works in the 'real world' for the same reason every time. Namely holding your arm[s] out in front of you for extended peroids of time is fatigue producing. A state that has come to be called 'gorilla arm' which also seems to have to be rediscovered every decade.http://catb.org/jargon/html/G/gorilla-arm.html
It happened to touchscreen technology in the 70's, 80's, 90's, amd the 21'st century. It happened to VR in the 80's and 90's. And it'll happen again with these motion-based systems.
Not to say something like this won't find a niche use. Motion-based systems like the wiimote or kinect work well for games. Just as touch based systems ended up working well for moblie devices because we don't use a cellphone or tablet for 8 hours streight, but rather a few minutes here and there.
Leap Motion looks interesting because it seems you could set it up to use it along side your keyboard and mouse - no holding your hand out infront of your face. Or Microsoft's kinect for windows which would also be an addition, not a replacement for, a keyboard and mouse.
But this. . . I cannot see anyoneusing this to do anything for extended peroids of time.