European great swords are meant for slashing, for example. Breaking defenses, thats why a swordman is usually in possession of a shield. Daisho are meant for stabbing. Katana are incredibly light and easy to handle, which makes fights between users faster than european counter part sword fights. I myself own a daisho set and i can honestly say that the katana and the european sword are too different from eachother to say one is better. Disclaimer : i am not a weeb, my grandfather was a sensei in the art of kendo and kobudo, i have been practicing these arts since i was 6 years old.