I think that tox.chat is not using any centralized servers and it is open source software, but there are not payments built in.
unless you count the tox DHT seeders, but according to the logic, Bitcoin is similarly centralized (because of the DNS seeders to bootstrap addrman)
Looks revolutionary to me and it can have real use case with some easy to use app, having a phone number (Node ID) without an actual phone number, that nobody can shut down.
that's what tox does already. Tox is nearly 10 years old, so this new idea is not the first message/video call network that doesn't need a phone number