I'm not sure this is a worthwhile comparison. Because the idiom of parallel programming is the same as the idiom for sequential programming in FP. It's complete

I'm not sure this is a worthwhile comparison. Because the idiom of parallel programming is the same as the idiom for sequential programming in FP. It's completely different (and more difficult to make correct) in imperative languages. Which means it will be harder to maintain and harder to evolve even though it might be slightly faster in certain situations.