Yes, it is useful because it make your body better.

Let’s give an example: Assume you are in the shootout. You have the gun, so they are. You are quick reflect because you are trained, which make you moving and shoting better than those weeb on high.

Another example: You hear a gun shot. You run for 2km without breaking the sweat. Because you are training to enduring and stamia daily, you can run for a while without tired.

But I think, reflexing, enduring and stamia are most useful when you are in danger. Just act fast, and run the hell out of danger.

Yeah they panting like dog. Watch this: https://www.youtube.com/watch?v=QM6TWQsWFx4