Learning Haskell taught me about a lot of language features that I find myself reaching for in lots of languages. Examples include: destructuring, list comprehensions, currying, immutable data structures, maybe types, and algebraic data types.

The language has a lot offer. How much you want to take away and incorporate in your programming repertoire is clearly at the discretion of the student; however, to imply that it is devoid of transferrable value is a false assertion.