the use case is really decentralized communication. sure connecting to wifi is easy and accessible, 4g is pretty much unlimited, but what if you just want to share files/photos directly with a group of people without having to traverse the web/someone else's hw/sw? this is basically like a detached, private web. most of the time, you probably dont care if meta has your files, but for those that just dont like centralized services, this is great. think of it like an extremely private network, why not?