Real time / embedded / etc for money handling, healthcare, aviation/transport... And 'needs' is a loaded term; the biggest $ contributors to formal verification progress are blockchain companies these days while a lot of critical systems are badly written, outsourced things that barely have tests.

My worst fear, which is happening because it works-ish, is vague/fuzzy systems being the software because it's so like humans and we don't have anything else. It's a terrible idea, but of course we are in a hurry.