The demonstration that air resistance is the cause of the difference in fall duration is what you gain from this. You don't get to remove air resistance from the equation in any other way. It's easy for an ignorant person to assume there's no way air, something we "feel" no resistance from in our daily lives, would be able to fight the force of gravity to such a degree. This experiment makes that concept clear, where dropping a stick and a lead pipe from equal height would not.