true enough but...
Its true a sword never runs out of bullets, but a stockpile of bullets will last longer than one sword arm. I mean, I don't care how good you are, get about a thousand zombies around you and your going to get overwhelmed, gun or no, but your arm would wear out alot quicker with a sword than say a rifle or an uzi.
Also, if your sword dulls, it takes ALOT longer to sharpen a sword than to cram some bullets into a gun.
that and the distance advantage are why the samurai were wiped out by gunmen.