Recently, I've been going around and creating tag wiki excerpts. At first, I was wondering about the usefulness of such work-but after a few accepts, it seemed like a good idea. After a few (not-so) stupid blunders, I got autobanned from editing. I know, a tragedy. Please, save your gallons of tears for later, we need to focus :)
Naturally, the first thing I did was lament in the site chat. Out of the blue, a user came along and pointed out that my edits were technically against the policy for good tag excerpts.
Now, I am pretty sure that this is part of the "default" kit assigned to all SE sites, but the point still remains.
Most of our tags are about the content of a question, not the question itself. Thus, according to the policy, there is no need for a usage guide-the exceptions are tags such as hard-science and internal-consistiency.
Essentially, should we even have such "boilerplate" descriptions of a topic on wiki excerpts?