Why nostr need a billboard to be promoted and make unnecessary noise? Remember Satoshi's words when Wikileaks announced they will start accepting Bitcoin? December 11 2010: "Wikileaks has kicked the hornet’s nest, and the swarm is headed towards us".
I think this idea of a billboard in Brazil is not good and will create even more problems. Better a natural adoption, only for those that really need it and know how to use it. Let the masses and the politicians into the darkness, clueless.