I suspect that the huge 2 handed swords favoured by the Landsknecht, were intended to intimidate people into not laughing at their clothing.
https://en.wikipedia.org/wiki/Landsknecht
Serious answer: They are for opening up blocks of pike men. You use the 2 handed swords to destroy the pikes and/or push them aside, then send your guys with short swords into the gap to destroy the pike block from the inside.
In Spain the big swords were called mandobles, they were used kinda like a maneuvereable spear with a far better angle cover to bash/defend.