I think it needs to be better known. It is increasingly known in privacy /open source circles. Which is kinda perfect. 

It's mostly unknown to most people I reckon. 

Does nostr need billboards? Do they work? I don't know. But this was a really fun idea :)  

 Yes, I agree.

I heard about nostr first about a year ago and didn't care because I was never really into social Media. I joined a week ago and discovered it is totally different.
So I'm a good example but a billnoard would never got me in.