When it comes to stopping power and effectiveness in a fight it's obvious that a gun is much better than the martial arts for such stuff. No matter how good you are in the martial arts and what skills you've got, it wouldn't be that smart to go up against somebody who's got a gun when you yourself are unarmed. However there is one main advantage that the martial arts does have over guns and that's how its viewed in court and dealing with the legal aftermath if you ever do use martial arts vs if you ever use a gun.
As the martial arts is nowhere in the ballpark in effectiveness in a fight when compared to guns, as such the way martial arts are viewed in court is nowhere in the ballpark with how guns are viewed in court. if you shoot somebody, even if its in legitimate self defense, you can expect the courts to come down really hard on you. You can be looking at both criminal and civil charges. If on the other hand you just use your hands, feet, ect. to deal with a troublemaker in a confrontation the court will be most likely much lighter on you. So that is an advantage of not using guns or any weapons for that matter, you're not going to get in trouble with the law the way you would if you used a gun, or for that matter another weapon such as a knife, stick, ect.
You could even use that as a defense in court, that you didn't use a gun or any weapons. You could argue that the martial arts is not the same as a gun and as such the courts shouldn't be hard on you as if you did use a gun. So that is the main advantage of martial arts, in self defense.
“Stopping power” is a word often thrown around by people, without knowing what it means. The main difference between other weapons and a gun, is that the gun achieves force at distance. Well, technically you can use a sling shot, or throw something, but it’s a hell of a lot harder. I think the only successful throw I’ve seen, was footage of someone tossing a traffic cone onto someone’s head, in Glasgow.
“More lethal” is another one people like to throw around. If you shoot someone in the T-zone, stab them in their left ventricle, throw a pipe at their temple, or bang their head against the edge of a hard table—the result is the same.
Lethal force is lethal force. Some places care how you apply it, others only care if it’s justified. Some of that is explicitly written in law, some of it is jurisdictional culture.
Violence isn’t a movie. You’re not gonna pull a Jason Bourne, or a Road House unless you’ve trained for decades into particular areas of martial arts. Even then, it’s always 50/50. You may beat him up, but you may also drop dead in the process.
A lot can happen once that first punch is thrown, and just because you were unarmed, doesn’t mean you’re safe legally.
Self-defense training, without providing context for the use of force continuum, deescalation, avoidance, and talking to authorities after, is not proper self-defense training.