Swords are a tool in survival beginnings. Even if you are a peaceful player you should always make a sword, you can technically hurt other players with an axe or a pick, but only the sword has a large Range
The sword is used in combat against other players, wether it be defence or offence. They are one of the first things you should make with a new metal, as other players pose a big threat. However, the sword is the most expensive tool in its tier, excluding the Club which is the cheapest sword its tier. But it's still advised to get a Sword for combat.
The better material the sword is made of, the more damage it will deal.
"Be polite, Be efficient, but have a plan you kill everyone you meet." -The Sniper