Efficiency was, is and always be a part of paintball. If it wasn't, 3000psi or less would be the standard rather than 4500psi.
Also, remember that this is smaller paint which means that you can fit more into a hopper and pods which means that you are going to need air to shoot all these extra pods OR the same amount of air but a more efficient marker.
''But the balls are x% smaller so that means x% less air needed to shoot them!''
Not necessary the case, fluid mechanics is a complex area with scale factors and all that funky stuff. There will be some reduction but not by as much as you may think.