Silberengel on Nostr: It's checked against an organisational domain server, like an e-mail server, rather ...

It's checked against an organisational domain server, like an e-mail server, rather than a list of npubs. Npubs who show up with a particular domain get categorized for everyone looking at the client, and the community client defines which domains are significant. You could even change the interface depending upon which domain they belong to. It's a group adherance.

Badges are for roles. They signify something about some particular person, within a community or across communities.

You can use either for both, or split them up.