Since the pyramids used to be covered with polished limestone and the internal structure wasn't visible, why didn't they use smaller blocks that could be handled more easily?
The bigger the block, the smaller the total surface you have to cut and polish. Up to a point, it's just less work to drag a large block around than it is to cut more smaller blocks, especially with the very primitive tools the Egyptians used. They actually cut stone by hitting it repeatedly with a slightly harder piece of stone.