To OP, you have power over selecting the correct answer. You should have had the person leaving the comments answer the question and select their answer. I've noticed, with how functional Vim is, that people are extending other people's answers and getting credit for them so really its just like the Wild West, do whatever you want.
Before posting a response to a question (that has been up for over a month) with no "answer" I came here to see if anyone has asked this meta question. The answer was super simple, and someone had made a comment to answer rather than make an actual answer that could be selected.
Since the question cannot be considered "answered" without selecting a posted answer it stays open indefinitely. If there are 0 answers many times people will not even look at the question, missing out on the comment. I find it a little annoying that all the SE sites have this occurring. I'm sure I'm reading into it too much but I feel like people seem to want to post in comments as soon as they have the privileges rather than when a comment is actually necessary. You'll see this on new beta sites where everyone has low privilege and then all of the sudden everyone wants to answer in comments rather than answers.
So I did the courteous thing, stated "Per so-and-so's comment..." and answered the question. Now I should restate, the comment had been posted for almost a month so the person leaving a comment should have had enough time to post their answer correctly. I'm not seeking points, I'm just trying to get the answer correctly marked down so that when someone does a search they won't see "0 Answers". If the person leaving the comment decides to answer I'll gladly delete mine to give them credit. I just find it insufferable that people feel like comments are the place to answer a question.
Sort of an aside, I can see cases where people feel its appropriate to answer in a comment. In Vim there are many times when someone asks a question and due to their lack of knowledge do not realize that their question either does not make sense or makes a wrong assumption. I think people need to start using a little better judgement on how a comment would work here. My specific case was someone asking how to apply normal mode commands to ranges, however they didn't know that was what they were asking. The person leaving the comment stated "Oh you are trying to apply normal commands so just use
normal". This is a perfect answer and something that a LOT of people will run into. Did they feel it was too simple of an answer? Did they feel like the new "cool" place to answer was in the comments? Did they feel that because OP didn't ask the "correct" question, it didn't deserve a real answer? Doesn't matter, they should just have answered the question.