The relayed signalling in CA11 is meant for small event-like messages, not for media streams. The goal is to establish a secure e2e encrypted messaging channel between nodes(browsers) on an open, untrusted, overlay network. The network relays these encrypted messages between nodes. The messaging is primarily built for SDP/ICE and node discovery, but can carry any JSON data. The initial purpose is to see if this can act as a decentralized telephony system for p2p calling, using STUN and TURN. This would be an alternative for SIP-based calling(CA11 also does SIP). Afaik TURN just relays application data, which is already encrypted with WebRTC using DTLS/SRTP.
IPOP looks very interesting. I didn't thought of VPN use-cases yet. Thanks!