The server also handles arbitration which can add a ton more latency if you need to determine it via consensus from all the other clients. His lib is based on

The server also handles arbitration which can add a ton more latency if you need to determine it via consensus from all the other clients. His lib is based on real-world pain that many game devs have hit trying to integrate WebRTC. It's the same reason you see Lua thrive while V8/etc are rarely a part of a game engine.