Also any sort of combinator usage or functional programming reminds me of why static typing is so useful.

A few layers of higher order functions / combinators and I don't remember if I have `value` or a `{ value: value }` container (like map vs flatMap). Or which stage of the curry I'm at. Oh right, I'm at foo(a, _, c) but thought I was at foo(a, b, _).

If you can't even remember the last time you've encountered a runtime error, you are by my definition writing trivial code or not writing much code at all.

Yes. I'm part of a long term support team - teams do their work and transition it to me. I support a lot of solutions at once, none of which I've built or been able to spend a significant time getting into the guts of. Having the code do a lot of the investigation for me is incredibly valuable. It helps me quickly build a mental model of the small slice of the code I'm dealing with.

If you need autocomplete for your object, that's a sign your objects are probably a bit too big.