Almost all current software engineering practices and projects rely on humans doing ongoing "informal" verification. The engineers' knowledge is integral part of it and using LLMs exposes this "vulnerability" (if you want to call it that). Making LLMs usable would require such a degree of formalization (of which integration and end-to-end tests are a part), that entire software categories would become unviable. Nobody would pay for an accounting suite that cost 10-20x more.