My old Motorola Atrix 4G from nearly 3 years ago had that. They incorporated the scanner into the on/off button. I never used it. I found entering a PW was just as quick and way more reliable. Apple will probably do a better implementation than Moto, but I doubt I would ever use it. Besides, a retina scanner using the front camera would have been way more cool, but I wouldn't have used that either.