I’m not a fan
If you are attacked by someone intent on killing you, and that vile scum is armed, you really, really, really need a gun and nothing else substitutes. Not your Tai Chi moves; not your vote in favor of that gun controlling senator; not your folding lock-blade knife; not your fists. Not 9-1-1.
One thing that is even easier to deploy is situational awareness and a stare that says I see you and figure you’re up to no good. Knock it off. You’d be surprised at the effectiveness of that.