While perusing the Close Votes queue that is nearing 90k questions, I found that I was marking a good number of the questions with this reason:
Questions asking for code must demonstrate a minimal understanding of the problem being solved. Include attempted solutions, why they didn't work, and the expected results.
These questions are usually very low quality and people rarely bother to compose an answer. Often they will have comments explaining why it's a bad question, or how to improve it.
I thought, "Oh well we are closing these because they aren't useful and we don't want to pollute our question pool", but then realized that putting them on hold doesn't remove them from SO at all, it just restricts some activity until they are improved.
So what are we actually achieving by putting these questions on-hold?
Other users don't appear to be wasting time answering them, so we aren't saving others time. We are, however, spending time flagging and reviewing them.