I feel like having a preference kind of defeats the point?

I thought they were supposed to be interchangeable?

It’s the communities yours supposed to care about.

I don’t really understand this either. I only have 1 account on Lemmy.world. I can see why some people have a backup. For me, it doesn’t seem necessary unless I’m missing something. If the server goes down temporarily, I’m fine with just waiting for it to come back. If it goes down permanently, then I’ll go ahead and create an account on another server.