You can save and vote from any instance. That is the point of the fediverse. You can have an account on lemmy.ml and interact with communities on lemmy.world.
Right, but then I have a separate set of saved posts and comments on every account. I'd have to try and remember which account I saved something under. It's a minor pain, but a pain nonetheless.
No you don't. As chris said, you can use the same account. I'm saying move communities off .world, not accounts. That way when it goes down, it doesn't hurt people on other instances as much (apart from being deprived of your luscious opinions for a few hours).