I’m fine either way. It’s cleaner to have it consistently denoted at local.intermediate.root authority structure. The @ prefix is just a notation thing that I believe was invented by Twitter, so in the early days @trbouma was exclusively Twitter but can now be generalized to express a full authority path. It would also work for @trbouma. as it would express names I have registered against the npub. It would be different that nip05 which is just a mapping to dns.