Various 'cut' testing has concluded that it is not just the sharpness, or angle that the blade is sharpened , but the 'polish' of the blade that affects cutting performance.
A highly polished blade has less drag as it slices and aids cutting ability. A characteristic of katana blades.
It does not make sense to compare a Katana to a Broadsword. Broadswords were heavier and generally designed to fight against heavily armoured opponents. The katana was not.
Regards David