A gun is useless unless you can put it into play quickly
A gun is useless if its on the bedstand in your bedroom while you're setting our your couch during a home invasion.
A gun is useless if its in your car while you're being robbed at an ATM.
A gun is useless if its in your car when some one decides to mug you on your afternoon walk.
On the other hand a pocket gun just might be the ticket if you walk around with you hands in your pockets.
You're ready and no one knows but you.