This is the major "magic wow factor" behind GPT. It has a basic level of knowledge in every topic which is enough to convince an average human that the AI produced a good result If-And-Only-If the human is unskilled in that topic.
Except that GPT can and does produce good results even to experts, just not all the time. So your claim of "IFF" is unnecessary hyperbolic contrarianism
The interesting part here is "does it take longer for an expert to come up with the answer independently or verify that GPT is producing an accurate result?"