I'm not saying it's a valid complaint; however, I don't think it's uncommon. I think the person in question was assuming that Haskell was designed for mathy/programming languagey type stuff (I'm being vague and mangling English because I'm tired :)).
This is a great counter-example: it's a project in a different field and, most importantly, the programmer enjoyed using Haskell for it. As long as it at least mostly works, the actual quality and polish of the project is immaterial--you cannot really expect a spare-time project, even in a perfect language, to be perfect; its existence alone signals that Haskell is a viable multipurpose language that isn't just a silly academic curiosity.
I strongly disagree that unpolished programs (done under time constraints or otherwise) signal that a language is more than something satisfying (academic) curiosity.
I am a contributor to the Yesod web framework (so I know this example is a good one - there are certainly others). Yesod is robust software used in production right now. Feel free to point people to www.yesodweb.com as an example. We are doing traditional IO-heavy database oriented web development, but leveraging Haskell to make things better in ways not possible in other langauges.
This is a great counter-example: it's a project in a different field and, most importantly, the programmer enjoyed using Haskell for it. As long as it at least mostly works, the actual quality and polish of the project is immaterial--you cannot really expect a spare-time project, even in a perfect language, to be perfect; its existence alone signals that Haskell is a viable multipurpose language that isn't just a silly academic curiosity.