Swords in general are fairly useless as military weapons go. A spear is better in every way when it comes to actual warfare between heavy infantry based armies. Even for cavalrymen, axes, maces, and lances are better.
And that's in terms of pure combat effectiveness without considering all the other problems with swords: cost of manufacture, maintenance, and need for an additional piece of kit in the scabbard.
But at least a one handed swords can be used with a shield, which is a universal necessity, a two handed swords is only practical in special situations when wielded by specialist troops. Generally speaking it can be used to break pike formations, but as we all know, close ranged pistol and musket fire work much better in this role.