It's a bad replacement for forums.

The Discords I'm active in are all everyday conversations, like big group chats. Some of them are funny/interesting and occasionally someone gives useful advice, but the vast majority are forgettable.

I think that people should publicly share valuable information (like great conversations or useful advice) and some of their typical conversations (a context summary for outsiders and history). But privacy and ephemeral-ness make people more open. It may be better to have a space for most conversations where they're not expected to be saved, or (because "not expected" in Discord relies on weak evidence and today's norms) guaranteed not to be saved.