How should we deal with good answers given just as comments?

Question

Recently I was browsing through the "unanswered questions" section, and I found many questions which had good answeres - but those were given as comments. Some of them are very short, but still a valid and sometimes satisfying answer, so maybe the original commenter did not want to post a one-liner as answer.

Unfortunately, the question remains "open" and is more or less a click bait since people read the question, read the comments ant feel like there is no more to say without repeating the comments.

I see two options:

1. ask the commentators to write their comment as answer - I'm unsure whether they would do it.
2. Compile an answer from the comments given. This feels a bit like plagiarism (of course you should cite them)

What's your thoughts about this issue?

Answer 1

My approach is generally to prod people who leave good comments into making them into answers, with sentences like "@username, if you posted that as an answer I would definitely upvote it!" That seems to work pretty well. If a few days later the answer still hasn't been posted, I'll post an answer of my own, using the comment as the core but also making a point of elaborating, extending, or providing evidence.

Answer 2

I very like Stella Biderman's approach, which is also probably the more common here. I don't like when someone copies a comment into an answer, without adding anything, just to avoid leaving a question unanswered.

However, I'd like to add a remark. I very frequently access SE from the Android app, especially during dead times (while waiting in a line, at the – ehm – restrooms, etc.). Unfortunately, the Android app makes far easier to comment than to answer, because when commenting I can read the question's text too, which is instead removed when answering. Thus, I tend to write a lot of comments, but later I might not have the time to expand a certain comment into an answer (or I simply forget about it). Maybe it's the same for some other people too.