Because the holes, or alveoli, help propel it. When the ball starts at high speed, it pushes the air in front of it, forming several currents that stop its movement. Each alveolus creates turbulence that keeps the main current closer to the entire surface of the ball and not just in front of it. With that, it increases the air pressure in the back, giving a bigger impulse. In the 19th century, when rubber balls appeared, it was noticed that the greater their wear, the greater the distance they reached. Manufacturers then proceeded to drill them with pointed hammers. In 1890, the coating was standardized and the balls were similar to the current ones, with up to 500 alveoli.
long reach holes Recesses make the ball fly further
On smooth balls, the difference in pressure between the front part (which faces air friction) and the rear part slows down displacement.
The holes, in turn, deflect the air current, bringing it closer to the entire surface of the ball. The deflection in the current increases the pressure on the back of the ball, which helps propel it along.