The Chaos Computer Club on why authorities are in love with biometrically unlockable devices:
“It is plain stupid to use something that you can’t change and that you leave everywhere every day as a security token”, said Frank Rieger, spokesperson of the CCC. “The public should no longer be fooled by the biometrics industry with false security claims. Biometrics is fundamentally a technology designed for oppression and control, not for securing everyday device access.” Fingerprint biometrics in passports has been introduced in many countries despite the fact that no security gain can be shown.
iPhone users should avoid protecting sensitive data with their precious biometric fingerprint not only because it can be easily faked, as demonstrated by the CCC team. You can easily be forced to unlock your phone against your will when being arrested. Forcing you to give up your passcode is much harder under most jurisdictions than just casually swiping your phone over your handcuffed hands.