The common way of managing ssh keys involves having some central entity that somehow updates the authorized_keys on all relevant hosts, which involves interacti

The common way of managing ssh keys involves having some central entity that somehow updates the authorized_keys on all relevant hosts, which involves interaction with all the hosts which is somehow triggered by interaction with the user requesting access. With ssh certificates the central trusted node only interacts with the user (by signing the certificate) and does not have to update anything anywhere else.