This was my challenge. Give concrete examples where you reason about programs better while programming because of the category theory. People have been arguing this for years without any concrete examples. I'm a math person and I would really like to use category theory and mathematical intuition when programming.

I argue that there is very little usable structure for reasoning for the programmers after the definitions. There is no buildup of structure that is common when mathematics is used effectively. The gain from math is very small or nonexistent.