Oh, gods, now Apple have announced face recognition we're going to have to have another outbreak of hot takes on why it's not proper security, aren't we? Like we did with fingerprints.
@ghost_bird You're about 6 months late http://thehackernews.com/2017/03/samsung-galaxy-s8-facial-unlocking.html
It's for convenience, not enhanced security, and all the clever ways to circumvent it you're thinking of? Never going to be useful for casual thieves, who are your main actual risk.
@ghost_bird birdsite full of mentions. anyone concerned about security knows a pin is the only way to prevent access from being compelled.