For especially sensitive actions, including changing the password of the Apple ID account associated with the iPhone, the feature adds a security delay on top of biometric authentication. In these cases, the user must authenticate with Face ID or Touch ID, wait one hour, and authenticate with Face ID or Touch ID again. However, Apple said there will be no delay when the iPhone is in familiar locations, such as at home or work.
My first thought regarding this bit is that it’s sure going to slow things down at the Apple Store, where password resets are very common support issues. I’m guessing that Apple has thought this through, though, and has a solution. The online self-service tool, for example, might not require a time delay or biometrics, which might be damaged.
And if not, well, that’s why this will be an opt-in feature.