Yes true, Briar is also able to do this and has worked over bluetooth for years. I would seriously prefer Briar over Bitchat for this internet-is-down use case.

And #LXMF #Messenger like #Sideband It does replicate itself even without internet. Because #Reticulum is much more. It's a whole network stack. 🕳️🐇 Study Reticulum: https://reticulum.network/