Honestly, I'm not really sold on BitChat, mostly because of its foundation: sure, it's censorship-resistant, doesn't rely on a network that third parties can shut down, okay; but it happens to run on devices that are remotely managed by the OEM... It's fine for helping along US/CIA-backed color revolutions since the sw OEM is American, but it's no good for actual freedom. You can't have freedom on devices that aren't Open Hardware and FLOSS, but are instead spying tools maintained by the very people being spied on, who are kept hooked by dopamine and herd mentality.

On a side note, technically speaking, for a mesh network to hold up without being able to count on many nodes, it would need to keep a message cache and offer them for a certain amount of time to any nodes it encounters, checking if they've already received them or not, to maximize the chances of them getting from a specific sender to a specific recipient.