> 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.

For the Google Pixel 4 that they are using in the video you already have a big display. It can instruct you how to gesture so that you learn it and later it can let you gesture without instructions.

> The second is what's known as the Midas touch problem. How can the system differentiate if you are intentionally gesturing as input vs incidentally gesturing?

Either an activation word like you said, or it could use the front-side camera to see whether or not you are looking at it.