This is ridiculous on several levels. Here are two.
#1: The pen is (probably) an infrared LED and can be made for $5.
#2: Why is it better to draw on an iPad while swinging your hand in the air?
Markers on paper are fun. And they’re especially fun for young kids who are just getting started with drawing. Putting your hands on a pen and making it move on paper is an invaluable experience–a necessary one, in fact. The brain learns by drawing, and the tangible part of drawing is crucial to that learning. An air pen is no better than an air guitar. Maybe fun for a few minutes, but ultimately a waste of time and a dissatisfying experience.