I think this is a big feature that I hadn't recognized until you phrased it this way. It allows a strategy of guaranteeing *at least 1* pin of your data if it's important, but from the application side, you can forget about the details of the data storage.
I doubt IPFS is fast enough to justify it over other strategies today, but it makes me think of a type of cache where if a CID can't be found, you might rehydrate some slow, cold-storage data and push it back out to the network.