[orangeboats]

>The topic is CG-NAT and port forwarding

You don't mention port forwarding without mentioning about hole punching.

Because what port forwarding is for, if not to ease the establishment of direct connections?

>You don't need to establish P2P connection

If you are seriously suggesting Server-Client Is All You Need (TM), I feel we might as well stop the discussion now. VoIP essentially requires P2P, WebRTC is much better with P2P. BitTorrent etc obviously runs on P2P.

Services that provide relays (for people who can't establish P2P connection) for free, can only do so because they expect most connections to NOT go through the relay, and so they could simply stomach the costs of running one small relay.