Let me make sure I get this straight: To unlock our new iPhone, we just need our face, but to purchase things, we have to put our finger on the back? I know Apple usually waits to do things the right way when it comes to new tech, such as waiting until Touch ID was really secure before implementing a finger print scanner.
Since it can be easily spoofed by anyone who really wants to, Touch Id is _NOT_ what anyone in the intel business would call "really secure". What it is, is fast, convenient, and "secure enough" in the majority of consumer situations.
But I can't help feeling insecure about this input method since so many companies have failed at it—not just in a small way, but massively. Apple will need to go to great lengths to convince me that this is secure as my whole life is in my iPhone.
We used to say that about wallets and little black books
If you were really concerned about keeping something personally embarrassing and/or worthy of blackmail on your phone, you'd want Apple to implement at least a dual authentication method, like requiring BOTH a fingerprint and a long password. Personally I'd also want an iris scan. Better yet, just don't do it.
In any case, if you don't think facial is good enough, THEN DON'T USE IT. Problem solved.
Having facial and IRIS recognition would be helpful for the FBI.
How so? The info doesn't leave the phone.
Now, if you meant that it makes it easier for the police to unlock your phone without asking, then yeah.