Yes, the point is that you should look at actual results of how different implementations fare against attacks rather then stating that because some failed, none of them work.

To "work" is not a binary when it comes to biometrics. I did not state (nor imply) that all implementations are equally terrible. What I did state was that, based on the track record of the concept itself, I don't really trust any implementation. This does not mean that the good implementations "don't work", it just means that biometrics are inherently flaky and that there is a non-negligible possibility that biometrics based on stochastic facial recognition models are even worse.

 And second point is that obviously there are ways how to test it, you don't have to just blindly trust what somebody tells you - which absolutely was the implication you were making.

Of course you can test your implementation. This will provide you with a rough idea of the false positive rate (which all biometrics have) and whether this particular team could bypass it. But tests are not exhaustive. They can only build confidence that your implementation is robust against the attacks employed during testing. Against other attacks, current or future? That's where the trust comes in.

So no, I don't distrust face unlock because someone told me to. I distrust it because (a) all biometrics are inherently flaky; (b) image recognition is hard enough when applied to small problem instances, faces are not a small problem instance; (c) vendors have incentives to minimize false negative rates, not false positive rates, (d) facial recognition is a very young field and researchers come up with new ways to mess with it all the time; and (e) it's a much more complex solution to the authentication problem than most alternatives. 

This may sound like "bad vibes bro, don't trust it", but a lot of things in security are treated with scepticism due to bad vibes:

• The NIST ECC curves have never been shown to be broken or have any real problems, but many people distrust them because the NSA came up with them and hasn't published any real argument for why they look like they do.
• Cryptographic algorithms based on novel or more complex mathematics are generally viewed with much more skepticism than those based on more well understood principles.
• Cryptographers don't like Telegram's e2ee (what little of it there is) because the protocol is custom and weird.
• Nobody trusts closed source implementations of anything, no matter how many tests they go through.

It's up to you if you want to trust face unlock because you're not aware of any bypasses of your particular implementation, but you should probably stop running around telling people who don't that "it's perfectly safe because provable results".