Expanding Beyond Mainnet

Ah, I see. Anyone can implement this, though, using custom resolvers; is there a strong benefit to an ‘official’ subdomain registrar for each chain?

They absolutely can - you can call claim on the reverse registrar to own the node.

I see what you mean here. One problem with this is that it restricts you to single ownership of a name; if you want to transfer ownership of the name, you have to also transfer all the records to a new node. It seems to me it’d be better to be able to just create UUID or sequentially numbered names and use one of those instead.

Even then, I don’t think there are advantages to this method that outweigh the cost of maintaining such a list. Gateways neatly sidestep the need for this.

Having to maintain our own RPC endpoints would be even worse! What would be the advantage over just hosting gateways?

Those proofs are a crucial part of the security guarantee. If we simply tell people to “resolve this on chain x”, all those guarantees go away unless the user happens to have a local node for that chain. Public RPC endpoints for those chains could simply return false results with no consequence.