If you lock your phone with your face, the police can unlock your phone, with your face, without asking permission.

Further, we are not that unidentical. One guy has been arrested three times because he looks like a guy committing crimes. A rubber mask, and sometimes a picture can fool most biometric scanners.

Biometric ID is not safe on the front end, and not safe on the back end.

It is, however, exactly what big-brother wants.