It's only $25.

I've been interested in playing with Haskell for a while but I've been put off by the need to setup existing tools. Having an all-in-one package with neat presentation, packaged libraries, and immediate feedback sounds like a great deal for $25.

I think the playground is probably its most unique feature. Other languages have it, but they're either too heavy to be practical (scala worksheets), embedded in a browser (python), or just not languages I care to work with (Swift). I love the idea of being able to throw some quick code together in a window, see immediate results and tweak things until I get what I want.

Haskell is particularly well suited to this king of workflow, everything being immutable and evaluating to a value. You can think of it as the best programmable calculator in the world.

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.

R cannot compile Haskell code.