Yeah that's right! If you simply say that this syncs to all my devices, it papers over, or abstracts if you will, the complexity of: secure enclaves/TPMs, symmetric sync keys wrapping asymmetrically encrypted passkeys, resident keys that support backup, keys that do NOT support backup, how biometrics are used, etc. etc.

With a password, I can write it down on a piece of paper and put it in my safe.

One of these systems is not like the other.