I don't think disclosure is necessary, but I think it can build trust in cases like this. "Please note that we used an LLM to rewrite our initial English draft." The reason to do this is that then people don't waste cycles wondering about the answer to this question.

I agree. Their LLMed English is much better than my Chinese.

Also, some of the very worst English I've ever read, has been technical prose, written by born-and-bred native English speakers with very high educational credentials.

Clear communication is important. The best idea on Earth, is worthless, if it can't be articulated well.