? If a website sucks and can't support multiple passkeys that's not a flaw of passkeys. It's a flaw of the website. You could make the exact same argument for TLS or 2FA or every other security feature.
If the developer fucks up the website/app, that is their fault and not a failure of the technology.
If the developer fucks up the website/app, that is their fault and not a failure of the technology.