I was reviewing this late answer, which is actually a question, so I flagged it for moderator attention. Then, I missed the feature of leaving a comment (which is available in the queue of low quality posts) for telling the user that he/she should have posted it as a question.
I searched the review in my history, opened the answer and wrote a comment... but some doubts remains:
Are moderators able to convert the answer in a question? (I see that the user has no questions, then I understand that the answer was only deleted).
Was the user notified (by any means other than my comment) that he should have posted a question instead of asking an answer?
Might that process be automatized in some way? (This is not a feature request, since I'm not sure that the feature is actually missing).
tl;dr... I suppose.