Comment As someone who writes English, not American... (Score 1) 30
...I can see this could be useful for preventing reviews that claim I can't spell or do grammar.
It needs to be opt-in, not opt-out - not only for fear of butchering an author's beautiful sentences, but also because some authors who self-publish in English are successful enough that publishers of books in other languages sometimes pay for the right to publish a translation. Those contracts are usually exclusive, meaning that the author agrees not to let anyone else publish a translation of that book in that language. If Amazon's AI generates one without the author's knowledge, the author could get hit with a breach of contract lawsuit.