Edit: after reading JoeAltmaier and thinking more about it, its a terrible idea. You cant change it, its easy to dupe. No. Just no.

Ill leave my original post though. :-)

Id argue its more or less the same as a pin. Both could be gotten past with a determined attacker or a generic setup(camera for pin/selfie).

Infact id say easier for certain people who post selfies on public sites, ripm. Cut and paste on x background.

The more i think about it, the stupider the idea sounds.