I think that's part of why people are so interested in his opinion in this case. The games programming industry has some very unique challenges, and the focus on squeezing every last drop of performance out of the stuff you write tends to make it a pretty brutal environment for programming languages. From his background as a voice of authority in the games programming industry it's interesting to hear his feelings on the merits/drawbacks of something like Haskell specifically from that perspective.

The fact that he's not a long time user, or particularly a fan of functional programming, but a relative newcomer to it just adds more weight as he isn't some known fanboy that's going to praise FP no matter what. He's got extensive background in C, and at worst, average C++ skills if not considerably better than that, so he makes a fairly good case study of how practical it is for a non-functional programmer (but someone who's really experienced with imperative/OO programming) to pick up something like Haskell and actually do something useful with it.

It's also good to listen to the things he doesn't like about Haskell, E.G. debugging, and see if anything can be done to improve that.