When you were a child and drew a picture on a piece of paper, did you feel the need to fill up the entire page? Were you told it was wasteful to leave empty space? That belief may have been okay then, but it might not be a good idea for your marketing materials now. Fewer words or less design means higher impact for the words you do use. You don't have a lot of time to catch someone's attention and too many words will get lost. Only the main words will be read anyway, so don't clutter your materials with information that won't be read. Using fewer words will help you stick to the main point. Keep it simple.