Fixing a draft used to mean regenerating the whole post. When a section didn't sound right, the new version would correct it and overwrite three others that were already fine, so I kept a corrected copy open in the Ghost editor, regenerated, and pasted the good paragraphs back in whenever a draft dropped them. Four rounds in, the post still wasn't right.
The revision step in the plugin came out of that. It works one section at a time: it changes a section, leaves the rest of the draft alone, and waits for me to approve before moving on. A fix in one place can't rewrite another, and nothing I've already got right is at risk.