By getting to know how much power you can generate in practise, defending yourself against an attacker will provide you with the best advantage. Working to your maximal capacity on a kick bag will allow you to discover the power you can generate from each technique.
Once mastered you will know which one would be most effective and in what context it should be used. One punch or kick is sufficient in some case, to stop or knock out an attacker, but not without preparation.
Power is subjective, related to size and speed, which mean that you are in control of how much is delivered. No amount of kicking, punching, or time spent training will make you improve any further once you have reached your physical limitation. Without power, regardless of how good your technique is, it will be ineffective. But once you are armed with the knowledge of your physical abilities through those drills, you will be better prepared than most.
