I can't roll with the 'it's like calculators' brigade, but perhaps that's just my own bias towards language and writing in general terms.
@Stevicus, I'm sorry you were given memory tests, but really, the point of writing a persuasive essay isn't to establish in a student an established and defensible position about whether climate change is real, or intervention in Ukraine is warranted, or whatever.
It's about learning how to structure an argument. I would argue that schools should probably broaden the types of writing, and the methods of argument students are exposed to (I think oral persuasion is woefully underdeveloped in many schools...and man, is 'oral persuasion' a bad choice of phrase...).
Suffice to say the issue here isn't one of students using ChatGPT to gather facts. It's the potential harm this has in enabling students to avoid learning how to structure their arguments, or independently validate and assess source information.
Still, I think it's entirely possible for schools to ensure assessment tasks are completed in school time, and not as homework. And that this would allow assessment of student ability, and better establishment of areas requiring improvement.
What I've seen firsthand in Australia from a lot of primary teachers I know is ignorance of the impact ChatGPT is likely to have. That would seem problematic.