Not disagreeing with you, but I can think of two reasons why you might use distinct keys from the one client (and use ssh config to enforce the separation) * Y

Not disagreeing with you, but I can think of two reasons why you might use distinct keys from the one client (and use ssh config to enforce the separation) * You want to present different identities to the world and don't want them being conflated, eg separate your github hobby projects from your employer organization. * You are using ssh certificate authentication, which isn't supported by GitHub yet, but you might be using it for other things, and GitHub should hopefully support it in the future. Since this relies on the name of the cert file matching the private key filename (eg id_ed25519-cert.pub corresponding to id_ed25519), you can't afaik have different certs active for the one key. Personally, I deal with this by simply having different private keys for different purposes, to avoid cert collision.