This has little to do with Haskell as a language, and more to do with this specific tool. Your argument is a little like saying about paying for an editor "For

This has little to do with Haskell as a language, and more to do with this specific tool. Your argument is a little like saying about paying for an editor "For example, VIM can do the same thing, too, or even better...". What you get is a nice looking environment with a built-in playground alá Swift's, that can visualise data, types and even games.