Well, you don't need all that much capacity. The penguins are into text-based adventure games running at dial-up speeds and the seals are table-top RPG players. Neither population has discovered online shopping.
Thanks for sharing that link. The test seems to be setting the bar pretty darn low, however. It's enough that you think you should be doing less of something, and others have criticized you about it to the point of annoying you. That includes things I would put in the category of bad habits rather than clinically actionable disorders.
Haskell's big pluses are purity and rigor. Most functions can't affect external state; they can only return results. Haskell also has strict typing, which is great for catching mistakes up front, and takes most of the pain out of using it through really great type inference. Unfortunately the community around Haskell is very small, so if you use it for a project larger than one person you could run into hiring problems.
Scala's big advantage is that it works well with legacy code in Java. Unfortunately it straddles the boundary of OO and FP, and making both programming models work requires a large and complicated language. I'd prefer something simpler.
If we were to take another swing at FP, I'd look hard at Scheme and in particular at the Racket system. The big plus of Scheme is a certain elegance, which is very appealing. And lots of people have learned Scheme in school.