I mean, I get what you're saying about from the user perspective the pin is the login, but the under the hood nuance makes things pretty different in the end when thinking more about what's happening.
Same thing with a fingerprint with a passkey to some service. The fingerprint itself isn't the login; you can't just go to any phone and press your finger and log in to the service. So the fingerprint isn't the login, its a part of the process on that particular device to unlock that particular saved credential that logs you in.
Same thing with a fingerprint with a passkey to some service. The fingerprint itself isn't the login; you can't just go to any phone and press your finger and log in to the service. So the fingerprint isn't the login, its a part of the process on that particular device to unlock that particular saved credential that logs you in.