I thought the same thing. As far as I know, it's not.

Bitchat it's a hybrid system: it uses Bluetooth mesh for local, offline communication and Nostr for internet-based communication.

GitHub

bitchat/bitchat/Nostr/NostrProtocol.swift at main · permissionlesstech/bitchat

bluetooth mesh chat, IRC vibes. Contribute to permissionlesstech/bitchat development by creating an account on GitHub.