Have fun remembering your truly secure passwords the rest of your life.
Remember one thing for the rest of my life?!?! Woe is me!!! What a terrible reality that would be!! One whole thing! I'm assuming you have forgotten your Apple ID password quite often huh?
Fortunately I have the mental capacity to remember one thing. However I only use a 4 pin passcode which is still arguably more secure. Hasn't everyone/anyone with a scanner on devices already played with it till defeat? They beat one on mythbusters with a photocopy of a print lol.
http://youtu.be/7sphAJFj9qA
Ever wonder why security is moving AWAY from that tech?
Guessing a passcode is a pain, and its simply that, guessing. Pulling a fingerprint is also a pain, but its not guessing.
And it's generally slower then nailing in a 4 pin code.
Nearly half the people I see with iPhones never use a passcode. So there goes any and all reason to upgrade for them.
It's just my opinion but unless there is other functionality for it besides unlocking your phone it just screams gimmick.
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Another thing to add is there will have to be an alternative unlock in case of a cut finger. So any security is still going to rely on a passcode. Similar to facial recognition on Android, when it fails it resorts to a passcode.
And anytime two methods of entry are allowed security is drastically reduced.