When thinking about somebody’s post, I often benefit from writing out my thoughts. Usually, I do that in a comment box, because that’s convenient.
Often, I’ll realize that my first thought is wrong, hit on something I want to read before posting, not have time to finish my thought, or feel growing uncertainty about whether it’s worthwhile investing the time to finish my comment. I don’t want to keep track of a bunch of half-formed thoughts on, say, Google Drive. So I delete the comment instead.
It would be nice if I could easily make and save a bunch of hidden comments on the post itself. They’d be essentially “draft comments.”
That's there to prevent losing data if you lose a tab, but it's not quite thereas a draft-comments feature. The part that's missing is the ability to get a list of all the posts/comments you have unfinished replies to. Which seems maybe worth implementing, I'll certainly put it on the wishlist, but I'm not sure it's high-enough priority that we'll get to it.