Not hating on your points, because they're valid, but the sudden transformation part of #1 strikes me as similar to when your hands are wet and you're trying to

Not hating on your points, because they're valid, but the sudden transformation part of #1 strikes me as similar to when your hands are wet and you're trying to use TouchID. The phone will shake the passcode prompt a few times and eventually give up and ask you for your passcode. I don't really see a problem with this. Apple has done a good job of making it known their biometrics aren't perfect, and will err on the side of caution when tested with strange inputs. You're not allowed to setup the phone without a passcode, and it serves as the final barrier to access if biometrics fail.