I have an iPhone and while I understand that Face ID probably has fewer false positives than fingerprint recognition, I really miss the physical rear sensor on my Pixel 2. I don't know what the collision rate is, or how easy it would be to break if someone stole the phone, but it was a really great user experience: haptic feedback is good, it was/is incredibly reliable at unlocking and it was useful because you could pass your phone to a partner/passenger in a car and unlock without looking (i.e. no more unsafe than changing the cabin temp) and no need to share your pin if with a stranger. I think the only time it failed was after climbing with chalky fingers.