People should generate at least a single ssh key per client device. (On Userify, rotating your key is just a matter of pasting the new public key into your keybox in your dashboard.) One per client device will let you revoke/rotate only that key when it's compromised. This also helps keep you from copying the private key somewhere else (which you should never do).
It does look like this wants to be a replacement for ssh-agent/ssh-add; also check out GNU keychain by Daniel Robbins, which is in most distro repos.
(blatant plug - we actually developed Userify for these three use cases, especially on cloud instances with constantly changing IP's)
People should generate at least a single ssh key per client device. (On Userify, rotating your key is just a matter of pasting the new public key into your keybox in your dashboard.) One per client device will let you revoke/rotate only that key when it's compromised. This also helps keep you from copying the private key somewhere else (which you should never do).
It does look like this wants to be a replacement for ssh-agent/ssh-add; also check out GNU keychain by Daniel Robbins, which is in most distro repos.
(blatant plug - we actually developed Userify for these three use cases, especially on cloud instances with constantly changing IP's)