The article linked includes OOB verification as a scenario in TOFU. From the perspective of the ssh client it's TOFU (no CA chain for the client to perform a check), sure, that just means it's up to the user to do the work and use ssh safely (either the server has a site posting the fingerprints like GitHub/the AUR or you're setting up the machine and have physical access, or maybe you're using SSHFP).

>If no identifier exists yet for the endpoint, the client software will either prompt the user to confirm they have verified the purported identifier is authentic, or if manual verification is not assumed to be possible in the protocol, the client will simply trust the identifier which was given and record the trust relationship into its trust database.