Sync in this situation means that the actual private key being used to sign in with the website is stored in a password manager as if it were a password, and th

Sync in this situation means that the actual private key being used to sign in with the website is stored in a password manager as if it were a password, and the service vendor (iCloud Keychain[0] for example) is the one that syncs the key to other devices utilizing that password management service. But this 'passwordless' trend is more about signing into websites - If they do implement singing into other devices, I don't think many people will do it (but it's possible - Windows Hello already allows you to sign in with a security key and disable signing in with the MSA password). 0: https://developer.apple.com/documentation/authenticationservices/public-private_key_authentication/supporting_passkeys https://developer.apple.com/documentation/authenticationserv...