Sure, public keys work as domains. Did you see the main issue I outlined though? This NIP literally siloes you into the relays you’re connected to & the relays they’re in-sync with.

If you try to resolve an NNS outside of that corner of the network, you won’t be able to resolve the IP. This literally centralizes the Nostr network. 

 Sounds like a great way to totally break the outbox model. What happens when I want to connect to an outbox relay and none of my current relays have its NNS? It literally breaks.