Leather bound? Definitely more about the shelf presence than new reading material. I've flipped through a friend's copy, and the paper quality is noticeably thicker, almost creamy. The gilded edges catch the light in a way my battered paperbacks never will, and there's a ribbon bookmark sewn in, which feels surprisingly useful. The illustrations are the same as the regular illustrated editions, I think.
But honestly, the 'exclusive' part is just the feeling of it. It's for rereads, for display, for when you already know the story by heart and want an object that matches the weight you give it in your head. I wouldn't recommend it as a first purchase, but as a milestone gift for a superfan, it makes sense. Mine sits next to my grandmother's old dictionary.