My answer with
This improves the readability of the question for those who come across it later...
was given in the context of a question that was already thoroughly resolved, and the issue was how to archive it better.
For an active proof-verification question, I'd expect the question body to contain everything that is needed for an answer. Separating the proof to be verified into an answer box has the following disadvantages:
- Reader has to look at two text boxes instead of one; this is annoying. Especially if another answer is posted by a 3rd party: now one has to look among the answer for the answer that contains the solution to be reviewed.
- If someone upvotes the answer for any reason, the whole Q&A will appear "answered" (i.e., will be removed from unanswered tab) even if nothing whatsoever was posted about the proof.
- Some users filter out questions that already have an answer (I do, at least). So, if a question is posted with an answer to it, I will never see it.
As an aside, Code ReviewCode Review is a Stack Exchange site that serves a purpose similar to solution-verification questions. As you can see, questions there are used for the material what is to be reviewed, and answers are used to critique that material. Makes sense to me.