Galène is not peer-to-peer: it's a traditional centralised server, where all media traffic goes through Galène. TURN is only used if the user's network blocks the UDP traffic between the client and Galène (TURN can use TCP, and can run on an unblocked port such as 443 or 1194).

Before Galène, I experimented with a pure peer-to-peer system, with end-to-end encryption. I found it to be too unreliable for group communication: with just 5 people in a group, you need to establish 10 peer-to-peer WebRTC flows, and the likelihood that all of them work well is essentially zero.