Real-time applications and really low-level systems software (however, there are some EDSLs that enable you to write real-time applications with Haskell's type-safety guarantees that can generate C-code: Haskell's Ivory library https://ivorylang.org/ivory-introduction.html).
Cross-compilation of GHC used to be a huge pain in the ass but that's improved significantly these days, on a project a few years ago I had to choose another language/ecosystem due to that limitation but I wouldn't have to now.
Could you discuss the niche exceptions you mentioned?