This might be worth a read, just as its from a trusted source and is more grounded: https://antirez.com/news/158
"In the past week, just prompting, and inspecting the code to provide guidance from time to time, in a few hours I did the following four tasks, in hours instead of weeks"
Its up to you to decide how to behave, but I can't see any reasons to completely dismiss this. It ends with good guidance what to do if you can't replicate though.
You could always test this yourself. Draw up a design doc for a problem, and implement it. Then ask an AI to do the same thing. Compare your time.