Comment by valorzard

So, having talked to people in the WebRTC community about this, you should be able to use WebRTC in a local network without having to connect to STUN/TURN

STUN/TURN matters because if you are connecting to a remote peer, you have no idea how to reach them. STUN/TURN gives you a "map" to get to the remote peer.

If you are on a VPN that doesn't matter very much (see: Hamachi)