I would use it to keep my public encryption key, my name, and medical emergency information (In Case of Emergency, or ICE). If push comes to shove, the ICE would be the top priority.
I have one of the first generation rings, but could never really use it because, unfortunately, I'm a klutz and have to keep my devices protected in cases, etc. and the NFC won't reach through them... So, I'm definitely interested in this new ring.