I agree. It also works well for small differences between communities. For example a Lemmy.world gaming community might not allow discussion of piracy and it is allowed here. This instance also has rules against NSFW content and another instance might not.
The communities on different instances are not the same. You can subscribe to both. The idea behind federation is that one company/server can't control all the traffic. It might result in a little splintering of communities, but I think it's ultimately better to be decentralized.
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