>Haskell is far simpler

I disagree. If anything, both Scala and Haskell are comparable to C++ in terms of complexity. Haskell is in fact, a bottomless pit.

During your descent into madness, you may encounter functors, monads, comonads, free monads, higher ranked types, arrows, zippers, existentially/universally quantified types, GADTs, kinds, and the other 300 extra compiler extensions that people use on a daily basis.

Documentation is provided in the form of academic research papers.

Not that I'm saying it's not an exciting journey, but it is a long journey.