It is mostly used by those who wish to provide feedback 1-866-719-1006 or report a problem, such as a potentially broken function on the page. Even so, it typically takes a number of reports before they really do something. Not to mention actually responding to you, which might take days or never (the tattler is more probable in my experience).
Additionally, they use this to receive reports of offensive or otherwise non-political stuff, which is a whole gray area that many legitimate Facebook users are currently unhappy about.
