[fogus]

    Haskell's type system is Turing-complete

So? What does that buy you in the face of attempting to prove that your system can run with two simultaneous users? How does the type system prove that it can withstand a DoS attack? Likewise, how can it prove that your system properly handles the case where the user types some garbage into a textbox? How does it help prove that your system keeps running if someone pulls the network cable out of the wall? How does it help prove that you wrote the system that your client wanted?

[billsix]

True, and unit tests don't help with those concerns either. I'm confused by the original post and these comments. What are you trying to convey? Can you state your point directly? I am not understanding.