It is an more private alternative to Discord. Even tough they do not offer federation, self-hosting servers is possible, but self-hosting Dms is not possible. Matrix does not have separated voice and text chats in one server, aka Discord style. Is it better to use Revolt for now or create our own Federated Discord alternative?
Revolt: https://revolt.chat/
How did Discord become so popular?
By being first to a market of combing something like Slack and Teamspeak into a easy to use webclient.