There's always that one rule in fantasy worlds that no matter what other, more potent weapon types that exist, the sword is the one weapon type that is always held as the standard by which the others are judged, usually due to some ancient Infinity+1 Sword that just so happens to exist. Yeah, that's right, even compared to a powerful Wave Motion Gun or a crossbow shooting explosive shells, the fine blade always comes out on top. It becomes all the more persistent in a world where Heroes Prefer Swords and corresponds with the main character being a sword user, in cases where the overall weapon type roster is of limited availability to characters.