Exactly.
Stop with that TouchID in the power button nonsense already!
First, like you said, the vast majority of people wouldn't be able to access it.
Second, it would be a nice way to tell to all the left-handers to go f*** themselves. Not everybody is right-handed, so the only way to get access to TouchID would be via the left index, assuming you have long enough fingers (but forget the Max sizes).
No, really, bringing back the TouchID in the iPhone would be the dumbest idea of all time (unless they manage to come up with an under-the-screen efficient solution). The way to go is, like they did here, to maximize performance and security of the FaceID system. Not to go back.