Chris G wrote: [...]
I also think that 'selling' Public Key authenticated logins as 'passwordless' is misleading. [...]
Not really, because you're only typing the password in to allow the agent to access the key, rather than typing it in every time you access the remote system. Once per sit at the keyboard is much harder to shoulder-surf than once per connection.
I think I also struggled to find gnome-keyring documentation but I think the basic mechanics of loading the keys in should be similar to ssh-agent. It's the specifics of what key and passphrase does what that may differ.
Regards,