> I get the enthusiasm for functional programming and persistant structures, etc., but at the end of the day it's just an engineering approach. One of many, and there's room to do the work to choose between them.

I don't disagree with this but that's not what you said initially. You said "this is why FP sucks".

I definitely think that if your work is doing tight-loops where every micro-second matters, an imperative language will usually be the correct approach. I don't think anyone is (or would) argue against that point, including most Haskellers.

However, functional languages do simplify things with network/concurrent applications. There's a reason that something like MapReduce is popular. Something like Spark or Onyx is just simpler to do correctly and work with than trying to achieve something equivalent using C or C++; maybe this is just me.

EDIT: My bad, I was responding to the wrong person, this person never said FP sucks. I apologize!