Well they better have good weapons for high-level PC's that sided with NCR.
And I hope that there is some faction out there that uses rippers.
Hell, I hope that every weapon in the game is used by some faction.
Maybe it would be more common to find a Legion soldier with a machete but they can wield stun prods, rippers, plasma fists etc. It's just that it's less common.
Was kinda boring that almost no one in fallout 3 used sawn off shotgun or power fist or hell, even brass knuckles.