This template is a shortcut for writing <br clear="all" />, which acts as a section break. In other words, when this tag occurs in an article, it is saying, "Make sure all prior content has reached its end vertically before displaying the following material." When the content of a section occurs in multiple columns, such as when images accompany text, and the text ends vertically before the image does, the "columns" get out of sync with the text which they are intended to accompany. This template can be used to keep them in sync. For a visual example, see the Oni article, which has pictures that are meant to be seen alongside each specific subsection of the article. Removing the use of this template would cause the text to get "ahead" of the pictures which illustrate that text.