I've been one of the people saying "we don't need more users. we need quality over quantity" and i was wrong.
the way it's going, lemmy needs active users who post content sothat the network stays relevant. networks like the fediverse benefit from network effects and that means that if we have more users, that improves the value and quality of the fediverse overall.
So please, everyone, when you can, make advertisement for the fediverse in your personal area. Go talk to friends, make attractive stickers and put them everywhere, stuff like that. We would all benefit from it.
edit: source for the graph
They are separate but they are federated, they can see lemmy's content and viceversa.
Edit: addition: Their success benefits lemmy, this is the beauty of the fediverse, competition is not really competition, we all win.