According to this answer on Meta.SE:
You should Delete a post
- If the post is rude or offensive [possibly flag]
- [ANS] If the answer asks another question
- [ANS] If an answer is actually a comment (such as asking for more info, thanks!, etc.) [possibly flag]
- [ANS] If the answer is incomprehensible and you are at least a bit familiar with the subject.
- [ANS] If the answer duplicates another, better answer to the same question (e.g. a link-only answer where another answer provides the same link with an explanation).
- [ANS] Is obvious spam (tries to sell you cheap sunglasses) [flag].
- [ANS] Note that wrong answers should not be deleted: deletion is for answers that “aren't even wrong”.
A common theme among these guideline seems to be that deletion is reserved for not-an-answer's.
For the particular answer you linked to, I voted "Looks OK" when I reviewed it, since it does try to address the OP's question, albeit not in a very satisfying manner.