I'm cognisant about relay traffic burden. But I disagree that there is "no good reason".

NWS works great for low-bandwith apps. It's very useful for Cashu mints and in contrast to most other options out there, nostr can be used from a web browser. It's the ultimate "other stuff" adaptor.

About efficiency: yes, nostr is very inefficient but that's irrelevant with the payload size we're concerned with.