Good idea to link that one too, but this is a feature on Lemmy to have multiple communities with the same topic, no centralization so we aren't just reliant on one instance. For more niche topics, it might make sense so small communities don't get even more fragmented. However for communities like gaming, a broad topic, it should be fine to have on multiple instances
lemmy.world also has different rules than beehaw.org, so different content and conversations will be allowed. I for one, support the creation of your gaming community and have subbed :)
Honestly, I would argue that it's more of a "bug" of Lemmy than a feature because it leads to fragmentation of communities. But we will have to see how Lemmy evolves now that we reddit refugees are all here.