Thank you! Watched Words Reference Guide isn’t clear on the behavior for edits for many of the categories. But, unfortunately, that doesn’t help much; as far as I can tell, you can’t have the same word in two categories of watched words (at least, any time I’ve tried, the word has disappeared from the first list when I add it to the second), so anything I have in Require Approval or Silence can’t also be in Flag. So even if I wanted to do duplicate work to put words in both places, I’m out of luck, I think.
I understand that Require Approval is harder to apply to edits because it would require a whole infrastructure around approving post edits that just doesn’t exist. I think that’s the feature request here.