For me self defense is a system that protects me in three ways.
The first and most obvious is physical protection. I must be able to survive a bad situation.
The second is legal protection. Survival is most important. However, if I survive only to lose my freedom or standard of living do to crippling criminal and civil lawsuits then I still count that as a failure.
The third is moral protection. Surviving a bad situation in a legally defensible way is still a failure if I can’t sleep a night and end up spending a fortune on therapy bills because I killed or badly injured someone I didn’t have to.