The bank takes the cut anyway, it is by and large offloaded to the vendors. The bank takes a nominal “service fee” that I generally “get back” many times over in creditcard cashbacks etc, plus it ensures my purchase. Hard to actually see the benefit of using cash only.
They most certainly do not, my FaceID worked flawlessly with all of my glasses, invluding sunglasses even when I did not set it up with glasses