Leap Motion was recently acquired by a company that builds ultrasonic haptic devices. The standalone USB Leap Motion sensor is still available for like $80. I've done some work with it (and the haptic device) and it's extremely underwhelming. It's equivalent to voice dictation versus typing. It feels miraculous at first but there's a lot of edge cases (like hands going vertical or occlusion) and there's simply no good UX patterns for gestures. Keyboard and mouse is faster and more accurate in 99% of scenarios.

Google actually one-upped Leap Motion with Project Soli that's in the new Pixel phones It can track minute finger gestures in a much smaller form factor using radar. It similarly doesn't have any killer app that actually makes it useful for much of anything.