What I think he is saying is that because it is now on iPhone, more devices/services/whatever may be likely to use finger prints for auth. This is dangerous because you can't change your fingerprint in the unlikely case someone dupes your print. If more and more things rely on finger prints, the value of duping goes up, right? What happens when your prints are duped once?
(1) If someone has my fingerprints they still need my phone to do anything.
(2) Even with my phone there's a good chance it's worthless unless they also have my pin.
(3) Stealing my phone has also become worth much less unless you have my prints and the followthrough to make fake ones and again they'll want my pin in most cases because you only get 5 failed attempts with your fake prints.
(4) All of that takes time, during which I may be able to remote wipe my phone, making the whole exercise worth even less. And it takes money, again lowering potential returns.
It's easy to imagine (numbers pulled out of ass) that a thief could get a few hundred bucks for a 5C (no touch id) but say half that for the more expensive 5S. Maybe that won't hold up for various reasons (hey thieves will work hard to make those stolen 5s's worth more) but the principle behind multi-factor is sound.
A default Reprap won't be able to reproduce a fingerprint, but all it would take is increasing the reduction rate of the motors, using a smaller hole at the hot end, and a material that flows better (or increasing the temperature).
It would probably take a few tries, but seems well within a person-sized budget.
