And art for the sake of art is just your interpretation. Other people would call it art for the sake of a consistent experience. Take your i-devices: they have a consistent design for both the product itself and its UI. It's all sleak and modern and fancy. That's not more professional than anything else just because it's something Apple has done. I even suspect that you find it professional because you're used to that kind of style from regular business presentations and Powerpoint slides.Apple's design theories right now tout that ornamentation should be used to subtly accentuate aspects of the UI, and not be used for an overly gratuitous "art for the sake of art". Of course, this is subjective; it's nigh-on impossible to make everyone happy. That's never the goal of a good interface.
The problem here is that the UI and the game itself are not consistent in terms of atmosphere and art. So it's not "art for the sake of art" but art for the sake of a consistent design. And no, I don't think that the UI aesthetics in place are a fitting contrast to the game.