We throw that name about these days when referring to Ecclesiastes. The first reason is that it makes us sound sophisticated. Goodness knows how many frowns we would get from today's scholars if we were to impiously refer to the author as Solomon. The binding rule of higher critical orthodoxy is that all scriptural texts must be dated to at least three centuries after the time proclaimed by the text. Secondly, unless you absolutely must, it is a good rule to assume that the author is not who he says he is but someone else (most preferably a nebulous redactor from Babylon in the time of the exile). If these two rules are not kept one may be certain of immanent and swift anathema from the intelligentsia.
The second reason is that it makes us sound sophisticated. We maintain the best of both conservative and liberal worlds by merely referring to the author as "The Teacher". This enables the liberals to cheerfully assume that we are in accord with them, and the conservatives to observe how scrupulously we refuse to go beyond what is written (after all, the name Solomon never explicitly shows up in the text).
The third reason is that it makes us sound sophisticated. Almost like referring to Don Quixote de la mancha, which sounds so cosmopolitan that most hearers in our circles of friendship will not bother to discover that the aforementioned title basically means "Lord of nothing from nowhere." In the same way, when we use Qohelet instead of Solomon we are compelling people to believe that we are chic, up with the times. But in the end the Good Lord knows that all of our scholarship is a big, meaningless pile of futile thinking and foolish words. And in the end, when all things are brought to judgment, it will be candidly revealed to us and the rest of the world that we are really just lords of nothing from nowhere.