Five things a reader notices
Each draft is scored on its hook, clarity, structure, ending, and how closely it matches your trained style. The overall score is the average, so one weak area is easy to spot.
Fix the biggest problem first
Suggestions are ranked by impact. Accept the ones that help, reject the ones that do not fit, and rescore after you edit.
Catch copy that reads as generated
If a draft starts to sound like a template, the score flags it so you can put your own detail back in before it goes out.