because its all preference. i know people who are 6 feet and ride 7 inch high bars, and then theres people like me. ive ridden bars that are all sorts of different sizes for extended periods of time, and honestly these feel the best on my back. Im not gonna be the kid who says 'they make this easier, but this harder' because i really dont notice a difference when it comes to actual tricking, but the bars suit me and i like em.