it is a nice idea but I am afraid it is mostly useless if it is not paired with some hybrid solution
because yeah you can do some basic IRC-like chatting over Bluetooth but we are in the 2026 and people want to send images and stuff, and doing that over Bluetooth and with several hops on top is super slow and far from ideal
that is assuming you managed to convince enough people to install the app so you actually can have more hops and reach further away people