In case you didn't know, when you are carrying a sword in the game, you can't hide it, you can't put it away, and you need to wear the appropriate disguise in order to not become suspicious.
But, let's be honest here. When you attack a target with a sword, you're not exactly all "silent" and "covert." So, what is the point of this unlock exactly? To run around the mission area, slicing everyone you see like Jason?
I'm sorry to say this, but if you're playing Hitman, there is absolutely no point to this weapon. It's RIGHT THERE for everyone to see, and I'd personally be better off with a knife (at least you can hide a knife...).