Close up, a shoelace can be a deadly weapon. So can a joint of bamboo small enough to stick out of your fist by just a little. Everything’s a weapon. But only a gun is also a deterrent.
Remember the scene in Spaceballs where Lonestar subdues a guard with a can of shaving cream? Anything a weapon.
Anyway....I have a fire extinguisher in my car. If someone goes road ragey & attacks me in my vehicle, would a facefull of dry chemical be a good defense until it becomes necessary to deploy deadly force?