There are "businesses" that have communities, and want to own/manage them. Discord works much better than Slack as a platform for "official" managed open-membership communities; it's seemingly a use-case the Discord staff have put a lot of thought into.

Think: every content-creator or streamer.

But also: regular corporations that provide platform services that people build their own stuff on top of, such that people want to talk to each-other about the service rather than just talking to the corporation about the service. (The sort of thing you used to stand up a hosted forum for.)