Having a great sword makes a difference, in the way it handles, balances and inspires confidence on the user. Plus, in hand to hand fighting, blade would meet against blade, and the poorer blade would break. People don't seem to realize that the construction of a sword is both a delicate art and science, trying to obtain a balance between hardness for slicing power and penetration, an softness, to prevent the blade from becoming brittle and breaking.
For that reason, Chinese swordsmiths, like the famous Wu and Yue such as Ou Yezi and Ganjiang, were the among the earliest to realize the use of bimetallic construction. What the superstitious may attribute as myth and magic, the swordmakers were actually applying practical engineering and metallurgy. Bimetallic means that the sword is made of two different alloys. The first, around the cutting edges, is a sharper metal that forms the cutting blade. The second, around the core or the back, is a softer metal to absorb and cushion the impact, to prevent the blade from becoming brittle and break.
The Chinese call this process sanmai, or a three form sandwich construction, where two outer and harder metals form a sandwich with a softer metal core in the middle.