Because it can be easy to test the result even if you don't know how to come up with a solution ? If I asked you to build a light switch I don't need to know a

Because it can be easy to test the result even if you don't know how to come up with a solution ? If I asked you to build a light switch I don't need to know anything about EE to see that the light turns on/off when I flip the switch. LLMs often fail to provide functional solutions for non trivial stuff (not impressive) - and once you know more about the domain, you usually figure out that the light switch will likely burn down your house in few hours because it's overheating.