In my profile I get a blurb "Have you considered accepting an answer or starting a bounty for this question?" for community wiki questions I've asked.
Does it make sense to assign an answer to a community wiki question?
This boils down to differing opinions on what CW is.
On this site, we've used CW for many list-ish questions, which is not encouraged on many other SE sites - SO in particular. Answers really don't make sense in these cases.
When CW is used for subjective questions, there is often a best answer, even if it is still subjective - perhaps the person with the most experience, or the most citations, or sometimes, sadly, the only person who managed to answer with understandable grammar. In these cases marking an "answer" serves to give some closure to the question and as a kind of "super-upvote" for future readers.
This is most useful when the subjective questions meet the criteria for good subjective questions - in my opinion many non-CW questions on our site still fail these hard (e.g.), let alone our CW questions.