Missed the browser demo with routing. Perfect!
It was more an idea, than an actual need. I messed around with WebRTC at a game jam a few years ago for a P2P game and was wondering whether you could compile the network code for P2P and what that would even look like. Whether you would need to or even want to is another matter.
As @zcaudate1 pointed out probably easier with some sort of data sync across nodes, although our experience with games it was much easier to elect one of the peer nodes as the “leader” and send a very small subset of data closer to an event stream to and from each peer rather than keep all the state in sync for latency.
So I guess I was thinking a context where the (e/server part of the code runs on the leader peer, so for the leader that would be local, and for the follower peers that would be over the network.
Anyway, in practice client/server is much simpler and practical when it comes to real world apps. So no real concrete need/use case outside of weird hobby projects. 