I keep forgetting that this discussion is iPhone-focused. At this point, I'm thinking about other systems too, such as ATM number pads or entry pads for securit

I keep forgetting that this discussion is iPhone-focused. At this point, I'm thinking about other systems too, such as ATM number pads or entry pads for security gate/secure door systems. What if each button on the ATM was also a very fast fingerprint sensor? (What if the ATM had a cleaning device built in?)