That's when the kite is flying straight. The shape you see in the store is not the shape you see in the air, and the shape while flying keeps changing. The frame and sail severely distort out of shape.
Less distortion means more performance and more fun .
An important basic skill, and a form of exercise, is to pull hard on one flying line. It should make your kite turn extremely well and give you a bit of a workout in the process. With relatively poor turning, a drop in pull, or something in the kite breaks, or the kite falls out of the sky. You get hot performance and good exercise. More response to power input from the flyer means more performance and more fun .