Note that I'm not necessarily talking about copying answers from ChatGPT/GPT-3+ verbatim. One could also start from an answer generated by ChatGPT and then edit it to become a high-quality SE answer with reference links.
I think this part is not answered by other answers. The leading policy here stated:
If it wasn't created by you, attribution is always required here
There are issues with this policy statement.
Programmers generally use IDEs/linters/beautifiers. It adds spaces/tabs in code/pretty prints it. Sometimes, it even fixes some bugs based on inbuilt syntax trees. However, we generally don't attribute the tool. What if we used ChatGPT to lint and beautify the code instead of traditional tools? Do we suddenly need to attribute it now, because we used ChatGPT to do the same?
What about grammar/capitalization? If we used ChatGPT instead of Google docs/Grammarly(a add on) to do the same, do we suddenly need to attribute it?
What if the entire post is written by ChatGPT? But you research it for quality and add links, fix bugs in the code. Do we need to attribute ChatGPT?
All the above is a mix of machine generated text and human content.
A better policy would be
If it wasn't created primarily by you, attribution is required here
How would we judge what is primarily created by you? In other words, who is the major contributor of this work? If the ratio of work done by you to the work done by a machine is at least more than 50%, I believe we can attribute it to you - It's a case of a human using a tool to create the content - that's it. As with any quality standards, this would also be a case by case subjective evaluation.