It depends on the domain. In performance critical code, I agree that it usually makes sense to use an imperative language. However, not all code is performance

It depends on the domain. In performance critical code, I agree that it usually makes sense to use an imperative language. However, not all code is performance critical. Also note none of this is to say that fp is inherently incapable of high performance code - properly tuned Haskell can be competitive with C. Libraries like Streamly[1] are designed with extremely high performance in mind. But I agree reasoning about performance is much more difficult and requires more expertise. [1] https://hackage.haskell.org/package/streamly https://hackage.haskell.org/package/streamly