The plainest attack there is, and the feeblest on the table: a bare fist does little against anything padded and rather less against anything rigid, and a hand is a poor instrument for hitting hard things with. Boxers wrap their hands for a reason.
What a punch has is speed, a free hand to follow it with, and the fact that you are never without one. It is also the readiest unarmed attack to convert into something better — a gauntlet turns a punch from a nuisance into a real blow, and its Impact Tactical Advantage rewards a fighter who is winning the exchange.
A rigid helm, boot or gauntlet adds 2 to the impact — which is why a gauntleted fist is worth so much more than a bare one. Thrown with an off-hand or off-foot, the strike takes −10 and loses a point of impact.