The issue with Jamulus is that it requires a central server - which means it needs to be close to everywhere . It also needs double buffering and double compression. P2P is the way forward here IMHO.
"The only clear benefit to it..."? As I suggested, a significant benefit of the Jamulus model is that any of the clients can be "thin"; most of the computation is done on the server. You may be able to improve on this but disparaging it with silly criticisms isn't going to help you; there are thousands maybe millions of satisfied Jamulus users around the world.
But if any of the O(N^2) P2P links has unacceptable latency, eliminating the server would be counter-productive because the client-to-server connection may have less latency if the server is located appropriately.