It seems that some like to use the comments for a five word answer that when later is rebuked with a answer that is posted AS an answer, it gets deleted, like "what you want isn't possible." I think using a Magic 8 ball would give the same remark.
Or..there is some debating in the comments, and one of the users simply deletes all of his or her comments as noticed when the @user is used by the remaining comments. This leave a confused looking conversation that is more static than helpful commenting.
I thought the comments were to guide, get clarity, or otherwise enhance what the post or answer has, needs, or is lacking, etc..
If it appears as an answer, then post it as such and add the appropriate detail, no?