The purpose of hollow grinding a thick modern blade is to reduce the amount of steel ... and effectively make it behave like a thin blade. Why not simply use a thin blade? Other than the fact that the thicker blades ould have harder, more abrasion-resistant steel (holds an edge longer) and less susceptibility to chatter, all of which are desirable. So hollow grinding brings with it the advantage of a thin blade allowing for easier honing, whether freehand or guided.

Regards from Perth

Derek