The real argument is that if the keys change, you'll know about it, because OpenSSH will yell very loudly about it.

The random art is intended for _first time_ connections, where OpenSSH has to trust your judgement of the key's legitimacy because it has never connected to that host before.

It's not like it will hurt anything, but turning it on for every connection doesn't make a security difference.

yeah, i guess syncing around your known_hosts file to everyplace you originate an ssh connection from, would make more of a difference. So that way you minimize the making of first-time connections as much as possible.