There are three legs to the stool: specification, implementation, and verification. Implementation and verification both take low-level knowledge and sophisticated knowledge of how things break.
This is the same with compilers. Most of the time a programmer needs to know only the high-level language that is used for writing the program. Nevertheless, when there is a subtle bug or just the desired performance cannot be reached, a programmer who also understands the machine language of the processor has a great advantage by being able to solve the bug or the performance problem, which without such knowledge would be solved in much more time or never.
I am sure programmers cherish every case when they can do micro optimization but in the retrospect the high level cuts is what made the system fit the perf or memory budget.
2) unfortunately, LLM's, by their very nature (not having a model of what they do, are prone to introducing subtle bugs, i.e. it is like programming in high-level language whose compiler likes to wing it
If only you knew how the civil engineering sausage was made.
The amount of yolo'ing stuff based on vibes goes up when testing is expensive/impractical. They just paper over it all with disclaimers of the sort that would get laughed at for being non-starters in the software industry.