functional languages aren’t battle tested or imply they aren’t useful in real world problem solving

Yup, I never said that, though? What I was about was to draw a parallel between functional programming languages and explorations from several decades ago vs the new languages and explorations going into effect typing/capabilities programming now (and the long way ahead for those).

What I find interesting is that those pioneering FP languages never came to top the popularity chart, implying that I’m not expecting Unison to be different (but the good parts might make it into Java/C#/Python/… many years from now).