I think it kinda works, but it misses the mark in that you don’t need to ‘travel’ to another server to see the communities and posts from that server.

It’s more like every instance is a post office, and when you make a post or comment at your local post office, they also send it out to a bunch of other post offices. So when you rock up to your local post office (instance), you can see all the activity at that post office, but also all the activity that has come in from federated post offices.