I don't necessarily disagree with your conclusion, but I don't think the analogy to close votes applies here. 1. It's impossible to flag with a close reason if you have 3k+ reputation. 2. Closing a question without moderator intervention is comparatively easy, since it only takes 5 users with 3k+ reputation. Deleting an answer takes 3 users with 20k+ and, as I mentioned in my question, there seem to be a lot of posts with pending delete votes.

@TomWijsman: I read your question before posting mine. I know which answers can be flagged as not an answer, but I'm interested in whether I should flag a non-answers if I have enough reputation to cast a delete vote.