This is one of those discussions/debate that just go on forever, simply because nobody wants or can define 'art'. So it seems to me that the 'debate' pretty much boils to this: 'Art' is a word that, when attached to a certain form of expression, it automatically gives it a certain 'prestige'. So the question becomes whether or not we want to give the form of expression in question that same prestige as those that are already classified as 'art'. It's not so much a question of 'is X really art', but more like, "do we want to give X our stamp of approval by calling it 'art'"?
Literature, music, painting, sculpting, architecture etc are things that have had this label for quite a long time, so they're not really debated. Film is a relatively new medium, and initially there were many people that refused to dignify it by calling it 'art', but now most consider it as such. I suspect it's pretty much the same with games. And in any case, even if we keep debating on whether Super Mario or Zelda should be called works of art, I'd say that even going with what most people mean when they call something 'art'(even if they can't define it exactly), you'd have a hard time arguing that films like "Battleship" are "art", or that games like Grim Fandango or "I have no mouth and must scream" are *not* 'art'. For games like the above, I don't think you even need to expand the definition of 'art' in any way in order to include them...any unbiased person would easily see that they're really as much 'traditional art' as any film.