Contact cards are great: https://github.com/nostr-protocol/nips/pull/761

But as you can see the entire "NIP" is actually just an event schema definition. It doesn't say what relays to use or give any implementation examples or UX suggestions.

Another argument for doing this:

nostr:naddr1qqyrxvf3vgunjwt9qyghwumn8ghj7enfv96x5ctx9e3k7mgzyqalp33lewf5vdq847t6te0wvnags0gs0mu72kz8938tn24wlfze6qcyqqq823czkn5qp