Dunno haven't checked yet. but at it's most basic level: "npub1 and npub2 briefly coordinate on some relay to share their IPs and other peering details, in an encrypted manner" doesn't sound like it "shouldn't work". Probably just weird ergonomics and complexities of strange home LANs, IP cycling, etc. It's essentially just a well-known "place" to discover each other and upgrade to p2p. The first bit is usually the hard or at least highly centralized part. At least in the sense of mapping a "name" to a device peering strategy. Like imagine we know each other's email addresses and wish to p2p with each other... there's nowhere to go from there. if we know each others's npubs and our clients are aware of the relevant NIPs, we have a path.