I think what's distinctive about it is how unformed it is. It's a great study in soft world building. If you're interested in world building, I strongly recommend the videos by Hello Future Me on this (and every other) subject.
Here's the one on
hard and soft world building.
In quick examples, though, Middle Earth is a product of hard world building, where studio Ghibli does soft world building. Much is left unknown, unformed, unexplored. It's deliberate and is better that way. Harry Potter used to be this way too, and was better for it.