My main gripe with fingerprint sensors on the back is that it's easy to inadvertently smudge the camera lens when unlocking the phone. Some phones have/had fing

My main gripe with fingerprint sensors on the back is that it's easy to inadvertently smudge the camera lens when unlocking the phone. Some phones have/had fingerprint unlock on the side power button which is similarly convenient, although I actually don't mind the underscreen sensors that are most common these days. I do appreciate being able to sneak a peek at my phone by discreetly unlocking it at very oblique angles that aren't possible with Face ID.