I think answers in comments should be deleted.
Comments are intended to be used for requesting clarification from the author, not for answering the question. The comment box actually says so itself:
Use comments to ask for clarification or add more information.
Comments are supposed to be temporary post-it notes, not permanent answers.
Answers in comments don't normally contain enough information to be high quality answers. Almost all answers in comments lack an explanation - and even if they do contain one, it's typically not good enough to be worth answering with. However, if a comment spectacularly answers the question, it can be converted via community wiki.
Because this happens so often, following up on everything may be impractical. History with answers has shown that most of the time, people don't come back to edit their answer to include an explanation upon request (~85%). In the interim, while we wait, the additional comments will create more noise, and hide other constructive comments.
Consequently, I suggest we just delete comments that answer the question, and maybe in a rare, exceptional case, manually convert to answer or ask someone to answer.