The boneshape thing is always stupid because no one... actually cares about that. It's like trying to judge someone by if they have their appendix or not. The difference is there but it's also so wildly meaningless that pointing it out at all just makes someone look desperate.
Because you no longer have to manually position, scale, and rotate your shapes outside of the armature. You can fix scaling, rotation, and location issues without having to touch the boneshape again. It saves on time and hassle.