Well because you need the rest of the language to make your program tell your system to do stuff.

Turns out `IO` is the most essential and useful bit of a Haskell program. That part can be left to the programmers. Haskell has a lot of facilities for making that nicer to work with as well.

I find that when I tell folks I work in Haskell full-time you can see their opinion of you change on their face. I'm not some kind of PhD genius programmer. I'm pretty middle-of-the-road to be honest.

It's just nice to have a language that makes the work of writing BLOBS straight-forward.