>He puts it a bit too general, but against full plate armour, swords are nearly useless.
they are useless for penetration. The rest of effects are in place. The beauty and usability of sword comes from it being very convenient weapon to focus and amplify the power of your movement in much wider envelope of possible positions and movements - much better than any other type of weapon. Hammer/axe comes close but it trades in significant part of the envelope for penetrating abilities in other part of the envelope.
A spear or halberd were much more effective than swords.
Swords were partially ceremonial and partially "nobility" weapons. Walking around with a spear in town is tiring, because its big, heavy and awkward.
On the other hand, swords can be sheathed. They were expensive to manufacture, so they denoted wealth. And finally, they were effective weapons at the end of the day.
Pistol vs Machine Gun is the best way to compare a Swordman vs Spearman. It is said that you can train a Spearman in a week to beat even expert Swordsmen (with years of training) regularly.
Spears / Polearms were cheaper to manufacture, more effective in the battlefield, and easier to teach. Swords were more of a "city personal defense weapon", very similar to pistols today. I'm sure the HEMA players around here know how much that range advantage gives you.
A Halberd was perhaps the perfection of Medieval combat weaponry. A long spear-tip for stabbing, a strong blade for cutting, and a hook for pulling people off of horses. Halberds could definitely do a lot more than swordmen, at much cheaper costs.
I mean, what is a swordman supposed to do against a heavy-Calvary charge? Halberdiers also outrange Swordmen, and have stronger formations. The two-handed poleweapon can be swung with massive leverage that can break shields and cut through even plate with ease. While the stabbing point can be dug in to brace against calvery charges. It was an effective weapon at all stages of medieval combat.
The only swordmen on the medieval battlefield were the legendary "Double-paid" Zweihanders (The Doppelsöldner). But the massive swords these Doppelsoldners used were approximately the same size as a halberd.
But they were expensive, and the full-metal massive swords that they wielded were heavy, expensive, and required extensive training. (ie: more expensive) It was more effective in the long term to just train more Halberdiers, and the Zweihanders left the battlefield by the 1500s.
In any case, the "Longsword" is much shorter than these Zweihanders, and is at a considerable range disadvantage against spearmen. Mind you, King Author of legend killed Mordred with a Spear.
Swords were probably carried by Soldiers in case their primary weapon broke. They are excellent sidearms (like Pistols today), but I personally am much more comfortable with a pole-weapon (Spear, Pike or Halberd) than I am with a Sword. And I started with Foil Fencing mind you.
they are useless for penetration. The rest of effects are in place. The beauty and usability of sword comes from it being very convenient weapon to focus and amplify the power of your movement in much wider envelope of possible positions and movements - much better than any other type of weapon. Hammer/axe comes close but it trades in significant part of the envelope for penetrating abilities in other part of the envelope.