>>12Yes. Haskell is good to know, and often good to use.
Writing code in something like Haskell isn't necessarily harder, in fact I think it's easier if you approach it tabula rasa. It's often seen as hard for the experienced programmers because it's not closely related to anything in their language tree. You can't reach for the same tools, but you do get other ones, about half of which are there to prove the other half actually works and are being used correctly.
Right now, Rust is trying hard not to become Haskell (OCaml really) for systems programming. It's a shame in a sense, but they're really terrified of looking threatening to C++ programmers. That's valid in a marketing sense, but as someone who fights viciously for the future he wants to live in I would rather be a little more daring in hopes that C++ programmers will acclimate via network effect if nothing else. I don't want it to become Haskell, but a zero-overhead and more practical OCaml with idioms intelligible to C++ programmers where applicable sounds about right.