"reply" seems a bit odd when one adds to one's own comment.
Just noticed that I could manually override it for a comment, but I might as well never want to fill "reply" (the automated edit summary should do).
Topic on Talk:Talk pages project/Replying/Flow
If you were using your regular wikitext editor to post a new comment or answer someone's question, would you normally leave the edit summary blank?
generally yes, except when the section header isn't filled