.50 Caliber paintballs are relatively new technology in the paintball industry. These paintballs are smaller, lighter and more efficient than the standard .68 Caliber paintball.
The reduced size of these 50 Caliber paintballs means that related equipment (paintball guns, loaders, tanks, paintballs), are also smaller and lighter. This can encourage paintballers to carry more paintballs, thus increasing time spent on the field as they don't have to reload their pods/tubes or tanks as often.
Since the .50 Cal paintball has less mass, the energy carried during impact (even at 300 feet per second), is tolerable and less likely to cause excessive bruising. Impact energy at 300 feet per second is rated at approximately 5 joules compared to 13 joules from a .68 Caliber paintball fired at the same velocity.