1.i think this is different for all of us. some like the ability to have control at such levels, others like the loss of control, and some just like the rush, ect ect.
2. not just sportbikes, but cars, trucks, cruisers ect. too.
3.you simply havent found the reason for yourself to do so. you may find it or you may not. its up to you and entirely fine either way.