Originally the foam base was put on underneath the stucco because when stucco was used in places where it was not always hot and dry, the stucco would crack from the expansion and contraction.
It was only after doing it that they discovered the side effect in terms of cutting energy bills. I've been accused of being a Marxist, yet while Harpo's my favourite, it's Groucho I'm always quoting. Odd, that.