Apple "has made clear"... yeah, so, we must just believe them and shut up?
Not really. It wouldn't be the first time Apple lies (or at least shows its incompetence) about this (Messages). Plus, due to the NSA scandal, they are highly motivated to do so, so don't take their word so blindly. Any "mathematical representation" or model of your fingerprint
can (and will be) stored and reverse engineered: its just a matter of time.
It's incredibly naive (not to say stupid) is for anyone to think that
anything you put into your phone, and the internet for all that matters, has
any level of privacy, regardless of what Apple, Google, Facebook or whoever says so to save face. Stealing our information, and making a profit out of it, is part of their business model. Don't fool yourself into thinking otherwise. And remember: this discussion is just getting started.