Areniere

Why handle-pass is more pleasant and less dangerous without being unhooked?
First the kite is no longer blocked in full power, you can manage its tensile strength (the shock-border) at any time, making the start and the receipt of the handle-pass much more enjoyable. Then the kite stay hooked to the rotating harness, so the physical exertion in the arm is much smaller and you no longer risk a tear in your shoulder. Next mistakes are easily forgiven, you can drop the bar at any time and resume later easily. And finally you can string a trick immediately after the handle-pass without having to get downwind to hook back in.
Beyond handle-pass the rotating harness simplifies all blend receptions and makes navigation as a whole more enjoyable.