It seems like a cool little project, and I appreciate that it's GPL licensed, but I'm afraid without federation, it can't quite fulfill the same role that Discord does, as they would need a sudden dramatic increase of funding to be able to support a large userbase on a centralized server, and having another centralized point of failure is really inadvisable, IMO. A big reason for Lemmy/piefed's success is distributing resource useage across multiple independent servers, and that model translates quite well to a Discord like app too.

The project is also so new (11 months old) that it hasn't had adequate time to prove that the codebase could scale to a high user count. It's in a similar position to Fluxer.app, which is another GPL Discord clone, but one that is open to adding in federation at a later date.

I also think XMPP's encryption abilities are pretty essential going forward, as governments and corporations are becoming more invasive into monitoring our communications.