@Owyn similar to what
@jhadred said, usually swords aren’t meant to be razor sharp.
Swords, by design, are bashed against other swords, shields, armor, and bone.
If the edge is razor sharp, it gets thin.
And leads to a higher chance of the edge rolling or chipping. Being too sharp is bad.
Example, the edge on kitchen knives need to be constantly realigned. But it’s not a battlefield, so it’s ok there.
What “cuts” is usually the weight and force of the blade behind the swing. Humans are bags of flesh, metal isn’t gonna lose all that easily.
Also, on straight, double-edge swords, usually only one side is properly sharpened to begin with. (The other side often called the “false edge”)
You would sheath the sword with the false edge facing down, so as not too dull the true edge.
Having a false edge allowed you to brace the sword without cutting yourself, and not being fully sharpened, added some strength back to the blade.
Of course, in the case that the true edge gets chipped or damaged, and there are no replacement swords available, the false edge could be sharpened quickly into a usable edge.
Can’t remember where I learned this. I think it might’ve been a discovery channel TV show about weapons. Dunno how accurate any of what I said is, so grain of salt.