I tried it for writing, and while the main LLMs do a decent job of vomiting out somewhat wordy but essentially okay text if you want some kind of generic content on a specific subject, there's always a distinctly generative feel to it, at least in my impression. The real problems emerge when you ask for technical or datum-rich writing. The little invented or "mistaken" details are just too frequent to let it be useful unless you do enough editing that you almost might as well write what you wanted yourself.

Given the above, it's useful as hell for generating templates and usable starters for creating your own work when you're feeling stuck, and that's mainly it for me.