He never said that. He just said the "Haskell-ish beauty goes out the window," which is arguably true.
In my (limited) experience, Haskell code to do I/O (i.e., Monads) isn't a pretty or elegant as purely functional Haskell code. A lot of Haskell's useful tricks (i.e., its beauty like the ridiculously strong type system or lazy evaluation) don't work on code with side effects.
In my (limited) experience, Haskell code to do I/O (i.e., Monads) isn't a pretty or elegant as purely functional Haskell code. A lot of Haskell's useful tricks (i.e., its beauty like the ridiculously strong type system or lazy evaluation) don't work on code with side effects.