The fact that I don’t have to create any new account either way is very nice (no need to pick a side).

That's the only reason why I'm so invested in federated protocols :)

Of course it adds convenience if there happen to be a single place for the community to organize around, but you can subscribe to the alternatives and your feed wouldn't look different. I would also expect lemmy to, at some point, grow a feature to "link" communities together (like "spaces" in Matrix, that you subscribe to and get a list of related rooms/groups/communities in return).