There is a time between when a bug is fixed and when people can get that fix without having to pull directly from the public repo (which may be unstable). It's important for the writer of a bug to know when that bug is actually in a shipped revision, as well as when that bug was actually fixed in the repo.
Currently, we only have "open" and "resolved". We need a status inbetween that represents a bug that is fixed in the repo, but is not in any official distributions yet. That way, the user knows that the bug has been fixed, and will probably show up in the next version, but there's nothing to download yet.
This means that "resolved" should be what you use when a bug is fixed and shipping in a distribution.