@greyknight33 @ayy They learned it looked cool when they were making pirate movies. But pirates really carried two pistols because it took too long to reload a muzzleloader, plus you're not vulnerable while drawing out your sword after the first shot.
The only modern advantage is less arm arc movement in subsequent targeting so you can suppress fire with one hand while targeting with the other and then switch quicker with a head move as you're spraying to clean out a room.
And then there's