Right, like random-art or an ssh fingerprint. But still it would only be useful for address re-use which is bad practice in itself. (I could not think of another use)
Not necessarily. Any address, pubkey, transaction ID, block-header, Merkle root, etc. could be rendered this way. It could help ensure that you're not making any mistakes, at a glance. "Yes, I'm really working with the address I mean to be working with", which could be useful for ensuring you don't spend the wrong output and also for ensuring that you're sending coins to the intended address (there may be a time-lag between the time you receive an address and the time you send coins to that address, or you may be working with a large number of addresses and want to be sure you don't get the wires crossed).