Speaking as someone who has some training with a bayonet (US Army Basic Training), The advantage of attaching a bayonet to a firearm is added reach the firearm affords in close-quarters combat. That's why you attach a bayonet to a rifle. A pistol doe snot provide any added reach to the blade. Attaching a bayonet to a rifle essentially creates a spear. Trying to attach one to a pistol simply makes a very awkward knife. There is no practical benefit.But it looks cool.. Darn it.. Also, it could be useful..