From my (limited) experience with Haskell, my impression is that it's strongest in domains that map _very_ well to formal mathematical models. Mathematical computation is an obvious example, but things like programming language parsers are also really intuitive to build in Haskell.
My experience trying to use Haskell for other stuff — mainly, building web backends, my bread and butter back then — was painful. Simple CRUD against a database is actually pretty decent thanks to there being decent Postgres drivers and libraries, but the moment you need to handle arbitrarily-nested data structures (like a JSON request/response with a nontrivial schema), you run up against a lot of awkwardness, to the point that for the longest time this was known in Haskell as the "records problem."
Lenses and similar tools have tried to solve this problem over the years, and maybe they have, but I moved on from the language when I saw how deep that rabbit hole went.
None of this is to say Haskell isn't fun or rewarding, but it definitely has its strengths and weaknesses.