Hottake here:
The biggest mistake that the passkeys movement did is try to make it sound more marketable at the cost of oversimplification.
First up, these aren’t really “no password” mechanisms. They’re closer to ssh certificates. You need to authenticate through some other mechanism and then agree to do the equivalent of creating and installing ssh certificates on your device.
The ssh certificates get synchronized across your devices securely by your cloud provider. But they can never serve as the primary authentication mechanism - that will still have to be a traditional authentication mechanism.
It’s mildly infuriating that someone decided to take this simple idea and confuse the fuck out of everyone by positioning it as some alternative to a password based authentication mechanism. Obviously everyone is going to come and ask a ton of questions about how a mechanism without any passwords should work. And then the responses further confuse everyone because they don’t want to admit “no actually you still need passwords”
/rant