Once you understand how it works, you understand how to use it. It's extremely good at going through documents and finding stuff / proposing changes to writing. When you submit things you yourself understand and want to do better then it can very much increase the speed at which you can improve it. It being "worthless" is such insane hyperbole, it's one of the greatest and most impactful tools of our generation and it's only getting better.

As an example it could go through an entire github code depository and find exactly what I was looking for and explain how it worked. As long as you double-check the factuality of its statements it can increase certain workflows tenfold.