Question about the PhysicsSprite in the cocos2d-x Box2d framework


Who can tell me, in the cocos2d-x Box2d framework, why use the PhysicsSprite and rewrite the nodeToParentTransform method?
I know, PhysicsSprites can follow the Box2d bodies’ motion through nodeToParentTransform method, but why this way?
Is this way better than new a CCSpriteBatchNode, new some CCSprites, add those CCsprites to the CCSpriteBtchNode, and drive those CCsprites by the motion of the Box2d bodies?
If you know, please tell me the details, Thx.