I think part of the issue is that writing a game in Haskell is a novel challenge (it's running head-on into the weak points of the language), so the people who succeed make a big deal out of it. I'm not saying they don't deserve credit, but if they had used more appropriate language(s), the game would be judged on its own merits, you know? Similarly, I find kkrieger (http://www.theprodukkt.com/kkrieger) quite impressive. Not because of great gameplay (I don't even like first-person shooters), but because they fit so much into 96kb.
Half the original post's question is about learning functional programming. That's one of the niches where Scheme trumps almost everything else, and I also think Scheme is worth learning in general.