[x14]

No one should use FaceID OR TouchID to unlock their phone. For App Store Authentication, sure, because at that point it's just a second factor after you've already entered a passcode. Unless you're one of those "nothing to hide" type people, use a passcode, or better a password/phrasee.

[matthewmacleod]

Your passcode is almost certainly easier to divine than your fingerprint or face scan.

[lathiat]

Have you considered how easy it is to observe you entering your password over your shoulder? Or from a camera above.