It's good at writing. It's not good at knowing facts. If you give it all the relevant facts and ask it to do a writeup in a certain style it does a better first draft than a typical human, and in a lot less time.
If you ask it what the facts are, it just gives you a load of nonsense.
Even this is not always the case. I gave it a very rough draft and it actually made my structure worse, while at the same time using imprecise language. It looked like the correct style, but the content was not salvageable.
If you ask it what the facts are, it just gives you a load of nonsense.