Reopen votes are meant for questions that you believe actually have a chance on the site that were closed for one reason or another.
A typical example is a question where the author got shut down by the community, but you disagree. Another is on a non-natural close (moderator involvement) that you do not agree with.
Moderator closed questions, (at least myself) is saved for situations where it is obvious the question does not fit on the site and/or we have tried everything we can through editing and working with the original author to make the question viable. In those instances, I always encourage whoever wants to step up to make the question better to do so and flag for reopening.
I do recommend however, due to the small nature of this site currently, that if you cast a reopen vote, at the very least comment as well on the question and open a new Meta discussion about the question, that way your request is seen by the biggest audience possible for review.