[dignifiedquire]

relays _can_ be used to resolve IDs, but so can mDNS, an email or any other form of third party channel

[kiitos]

the use case here is somebody opens a web browser and types/pastes an ID into the top bar -- and it needs to resolve, correctly, without prior knowledge, in roughly the same amount of time that DNS takes today

relays are the only thing among the things you listed that even have a chance of solving this problem