Does a junior developer understand the core abstraction of a given project written in any language? Chances are the answer is no. Haskell just expresses that inside the language, while other languages tend to rely on design patterns, or just simply distributing the logic between many parts, which are arguably more error prone.

But for all practical matter, they can better write a single isolated case because it has to abide by stricter typing rules, instead of only conventions that supposed to he upheld.