Editing your own bad writing and editing a machine's bad writing are different jobs. With your own, you know what you meant. With a generated draft there is no intent underneath it, so you are reverse-engineering a point out of something that only looks like it has one.
The circulating lists of forbidden words catch the obvious cases and miss the structural ones: paragraphs of near-identical length, an unearned summary sentence at the end of every section, hedging attached to claims that were never risky. Fixing those changes the read. Deleting one adjective does not.
Whether any sentence would survive being read aloud, and whether the paragraph says something that could have been disagreed with. A tool that names what it changed rather than silently rewriting is more useful here than one that just hands back prose — this write-up of that approach matches how I ended up working, and it is unusually specific about the limits.
Most of what I do fits in free usage. I looked at the paid tiers mainly to work out whether volume was the thing being charged for, which it is.