It's tangentially related through the theme of decentralization

- It's trying to be a very decentralized chat application

- The linked post is on nostr, which decentralized broadcast messaging protocol

- Bitcoin is a decentralized money protocol

- Nostr has the capability to send bitcoin between users via the lightning network via https://github.com/nostr-protocol/nips/blob/master/57.md

It takes more effort to use nostr than it does anything relatively more centralized like bluesky or mastodon. So people there are the kind who are dedicated to decentralized technologies & support bitcoin.