>>The first is learnability. A big problem with gestures is that there is no clear affordance as to what kinds of gestures you can do, or any clear feedback. For feedback, one could couple Soli's input with a visual display, but at that point, it's not clear if there is a big advantage over a touchscreen, unless the display is really small.

That's the same reason for why I think voice controls are literally the worst way to interact with a computer ever(although I think this might actually top it).