Actually outside of a programming assignment, I think maintenance rather than speed is precisely why a company would want a functional code base. How much time

Actually outside of a programming assignment, I think maintenance rather than speed is precisely why a company would want a functional code base. How much time is wasted on debugging? Functional programming forces you to deal with your bugs at a much earlier point of development. It also forces you to avoid some bad practices just to meet a deadline. And since you're re-using so many component, you spend much less time with boiler plate code.