We actually had the opposite experience in hiring for our Haskell team: it was substantially easier to find legitimately strong engineers for Haskell than for other teams using Python and Scala. I figure it comes down to two things:

1. A lot more people want to do Haskell than there are Haskell jobs

2. Haskell is an easy way to signal (show not tell) that our team is willing to do things differently—especially important because our team was at Target, which did not have much of a reputation as a tech employer!

We didn't try hiring Rust programmers because the existing Haskell folks were more than happy to pick it up.

So making hiring easier is one of the reasons I'd want to use Haskell, counterintuitively!