My experience is that chatgpt consistently showed me API functions that don’t exist. But I tend to do very obscure things in embedded, that googling for can be tricky or impossible. At first I had high hopes, because the shape of the code is good, and the logic looks good, but when I go to look up details of the parts I actually need help with, they’re just made up functions, like placeholders I might write until I can go back and implement them.
Where it’s shined for me was writing code where I couldn’t be bothered to put together ideas from several distinct tutorials. It’s fantastic for writing code that you can basically google for, even if you have to read several disperate pages to get a clear picture of what to do.