Can someone more familiar explain the end goal?
Would a website want you to have to use Apple Passwords to guarantee that the account you're creating is connected to an Apple account, and thus making it more likely that you're a real, non-anonymous human?
edit: Why not just require "Sign in with Apple/Google" if that's the goal?
One requires owning the device you are using (which apple/google has default visibility into, and which becomes a data aggregator) the other does not.