Originally Posted by
BlazingPedals
Seems to me if the rotors are smooth (no grooves) then it's flat surface against flat surface and there's nothing to 'bed.'
You're wrong. When you bed-in properly, the surface of the rotors gets covered in an invisible thin film from the brake pads, which is more "grabby" than bare metal when the pads contact it. It also helps cut down the squealing issue.