Apple want there products to just work, face recognition does not it will raise all sorts problems for people. The idea of touch id is to make it easier to get into your phone whilst keeping It secure. Not to introduce some military standard of securing your phone.
So what if someone scans your fingerprint once? What will they gain? A frape, the dirty pictures you've been taking to send to underage girls? They can't disable find my iPhone or bypass activation lock or even change the fingerprints stored/passcodes without your actual passcode. Unless they keep the phone from ever locking again it's a pointless task to break into someone's house, risk getting caught by scanning the owners fingerprint *rediculius scenario* only to get outside for them to need it again!
So what are we actually going to gain. Give it some thought
So what if someone scans your fingerprint once? What will they gain? A frape, the dirty pictures you've been taking to send to underage girls? They can't disable find my iPhone or bypass activation lock or even change the fingerprints stored/passcodes without your actual passcode. Unless they keep the phone from ever locking again it's a pointless task to break into someone's house, risk getting caught by scanning the owners fingerprint *rediculius scenario* only to get outside for them to need it again!
So what are we actually going to gain. Give it some thought