Has anyone tried P2P messaging apps like Bridgefy or Briar while on a cruise?

Supposedly apps like Bridgefy use your phone's Bluetooth or wifi signal to create a peer to peer network. I assume this would not work well below deck if only one family had it installed, but there will probably be several thousand phones turned on at any given time during the voyage. If enough people had these apps downloaded and Bluetooth turned on, it might be a useful alternative for messaging (compared to buying the wifi package).

I downloaded bridgefy and Briar and plan to set them up on my phone, my family's phones, and a few old android phones I have laying around (to leave in our rooms as nodes).

Has anyone tried this either on a cruise, at a festival, or any similar experience?