I've seen quite a few such apps, unfortunately they are all incompatible with each other and useless if no one uses them.

But website design made me wonder. Is this (or any other) off-grid communication app being actively used in Palestine? Because if it is then it may be a best ad for when war eventually does come to my country.
- [I may be wrong about this but...] One interesting feature is that it can work in-grid. If I understand it correctly if one person in a group has internet access the groups can connect with each other.
  
  I think you are right, so far i haven't digged into it, but it would seem that it require the node with internet access that you are passing through to have some knowledge of the peers you are trying to reach.
- I don't know if it is used in Palestine. But i keep a copy of Briar offline, and now i will be keeping a copy of Qaul too. Briar had some momentum. But i can't say that i had any meaningful useage of it. Utlimately any chat app will depend on the type of network effect it can achieve. But yes, like you say: if war eventually comes, there will be momentum for meshed solutions. Well, given that someone kept made a copy before the internet went down 😅
  
  Briar had that one amazing feature that it can create a hotspot to share its apk.