If you want the messaging to be resilient, this makes sense as a server can go down but anyone else connected has the whole history on their server.

But I think that is better suited for a forum where copying Slack/Discord’s lead & trying to preserve all history in a chat isn’t worth it as I see this sort of thing as better tasked for ephemeral communication. However, there is something communal & intuitive about chat apps that make folks interact pretty well so they can make decisions. This is a ‘good thing’ where forums don’t get the same engagement—but at the cost of you had to be there or worse, you need an account to see the discussion for that decision.