The advantage is that the password never leave the device. It has a public key and signs challenges with the private key but nothing sensitive goes over the wire on every login
It should be noted that that is not an inherential advantage of passkeys over passwords. It is possible to achieve the same with passwords, e.g. by using a hash-cascade.
It should be noted that that is not an inherential advantage of passkeys over passwords. It is possible to achieve the same with passwords, e.g. by using a hash-cascade.