I'm not native speaker and many weirdnesses of the text may go past me, but I can say that for me the commented texts (especially the 2nd one, about post apocalyptic Canada) are completely passable and much better that what I will be able ever to write.
Yes, it may be not a threat (yet) to professional, especially established author. But they will be good helpers for people like me, who can get suggestions, improvements and illustrations just for the price of my 4090 and time to tinker with models.
No gpt was used for writing this though.