WebRTC doesn't need it either in principle. The stun server is only to exchange IP addresses for the purpose of hole punching through NATs.

Even in p2p implementations that use kademlia, you need a way to figure out hole punching. In IPFS, while there is a decentralised hole punching method as an alternative to a centralised STUN server, it requires atleast one participant to not be behind a NAT, so for this purpose it's besides the point.