Comment by nautilus12

Haskell done right (TM) is objectively by every means slower. Both in terms of implementation and execution. You end up trading maintenance cost related to design for implementation cost and maintenance cost related to scaling which I may argue isn't really feasible in a pure Haskell approach. I base this upon personally experience witnesses a haskell system serve something like 10 requests per second when a comparable implementation in Scala or rust or go could have easily done 10000