The goal for the game system is created to facilitate great stories. It's art, and no other piece of fantasy lore matches it in depth, breadth and consistency to my knowledge.

The amount of artists and writers who created it makes it art in my eyes. There's no other utility for it other than story telling either. If that's not art, what is it? The snobs at the Pulitzer who haven't even awarded a win to sci Fi novel may think otherwise but to each their own. In terms of the topic at hand, fantasy lore, there's few that can rival d&d.

Let's be real too. Baldurs gate and torment weren't made because of the great d&d gameplay system... The creators wanted to utilize the lore.