Well, it has a problem with my use of the Oxford comma, for one. Because a huge amount of the corpus is American English, and mine ain't. So it fails on grammar repeatedly.
And if you introduce any words of your own, it will sometimes randomly correct them to something else, and randomly correct other words to the made up ones. And it can't always tell when it's made such a change. And sometimes it does that even if you're just mixing existing languages like French or English. So you can make it useless for spellcheck by touching more than one language.
I do keep trying, despite the fact my stuff has been stolen and is in the training data, because of all the proselytising, but right now... No AI is useful for my writing. Not even just for grammar and spelling.
Writing is entirely different, and for some reason, generic writing even when polished (ChatGPT-esque tone) is so much more intolerable than say AI-generated imagery. Images can blend in the background, reading takes active processing so we're much more sensitive. And for the end user of a product, they care 0 or next to 0 about AI code.
Very interesting point!