When you are trying to impress people with words the more you say, the more common you appear and the more likely you are to say something foolish.
Power is in many ways a game of appearance and when you say less than necessary, you inevitably appear greater and powerful than you
By saying less than necessary you create the appearance of meaning and power, also the less you say, the less risk you run of saying something foolish or worse dangerous.
Once words are out they cannot be taken back. Keep them under control. In the tongue lies life and death. The momentary satisfaction you gain with your biting words will be outweighed by the price you pay.