Only in sense of exchanging data. the protocol. The app needs to undrestand data structures to operate.

Like curl can deal with http or dig with dns records. It doesn't know what to do with the data.

Frankly, I don't understand why I should choose nostr protocol instead of say dns (it's binary, fast, can hold arbitrary data and supports queries). 

 Check out WebIndexP2P which does exactly that. Fine tuned private nostr relays would be very similar to wip2p nodes.