What's the point when the server, if it's one you're logging into regularly (or even just more than once), will already be in your known_hosts file? Let the computer do the checking for you.

Showing the random art can help to notice if you connected to the wrong server by accident, e.g. Incorrectly connecting to staging.example.com when you actually wanted to connect to live.example.com

Good question. Perhaps it's useful if you're logging in from many machines/users without populated known_hosts? So if you spin up a new machine and push to Github, you can recognize it visually by its randart which you saw many times before on other machines.