No reason why any player shouldn't play mainline openings like the pros do. Maybe you think something like the Sicilian or the QGD is too "deep" or requires knowing too much theory in order to be competitive, and therefore you will be at some kind of disadvantage, but I say no, not when you are competing against players of a similar ability, who face the same issues with theory that you do.
edit: the point is, one's choice of an opening should not be overly dictated by one's rating.