I'm shipping massive amounts of code written in Haskell - production worthy for a real product - and the benefits of using Haskell over any other mainstream imperative language have been fairly significant.
I'm pretty sure Parent didn't included Haskell.
And anyway, my point was that you can do much much more than type level arithmetic.
Plus someone is seriously working on dependent types in Haskell - so no, I think it's fitting.