Let's not pretend voice isn't also a huge novelty. Yes the gestures are majorly a novelty, but the fact is, this is a radar, not a gesture sensor. It would be

Let's not pretend voice isn't also a huge novelty. Yes the gestures are majorly a novelty, but the fact is, this is a radar, not a gesture sensor. It would be capable of determining if you're in a dangerous situation (by sensing assault / weapons), it could help a blind person avoid walking into walls, or simply chime when it falls out of your pocket. Some of these have very high power requirements which is why it's not entirely practical to bake it into the phone as a common feature, but they're all entirely within the realm of possibility.