As a weapon/tool, the katana is basically over hyped. Yes, it's made by a very hard damascus-style folding, and it is very well constructed. However, most of that is unnecessary. Besides the ability to deflect blows from the sides, the Katana doesn't really have much else going for it. It has a very acute point, which can cause it to chip at it's point if used for a stab and comes in contact with a hard surface. It's easily beaten by chainmail and plate mail because it's mainly a slashing weapon.
The European sword, on the other hand, is more crude in construction, but achieves the same sharpness (I'll talk more on this later). It is more versatile, because it is less acute at the point, resulting in a tip less likely to break or chip upon impact with armor. It can still cause damage to people wearing plate or mail because it is heavy enough to cause bruising through the armor.
As for the argument of "The Katana is sharper" etc, this is wrong. Any metal can become razor sharp. I can take a crowbar to a belt grinder, and in about an hour, give you a razor sharp sword. Also, all that fine sharpening of the katana wears off after a few uses.
The European sword, on the other hand, is more crude in construction, but achieves the same sharpness (I'll talk more on this later). It is more versatile, because it is less acute at the point, resulting in a tip less likely to break or chip upon impact with armor. It can still cause damage to people wearing plate or mail because it is heavy enough to cause bruising through the armor.
As for the argument of "The Katana is sharper" etc, this is wrong. Any metal can become razor sharp. I can take a crowbar to a belt grinder, and in about an hour, give you a razor sharp sword. Also, all that fine sharpening of the katana wears off after a few uses.