i posted this before, but... it's still fun. no one (yet, outside of nerds & ppl on this forum) knows about back tap. so i set mine to invert the screen.
i tell friends i can invert my iphone screen with my fingers NOT touching the screen; i point 2 fingers at the phone with my left hand (while subtly tapping the back twice with my right)... and the GUI inverts. no one's figured it out 😂
other than that, it seems gimmicky to me, and don't need it. but cool if ppl find a, uh, more useful purpose for it.