I think the point is that you have applied self-defense component skills, but those skills are not self-defense. The self-defense is what happens when you defend yourself in real life. The skills were punching, kicking, blocking, etc., and that's what you learned. First you learned them simply, then you learned to apply them in wider circumstances, then you learned to apply them in more advanced ways (often, actually simpler ways), then you used them to defend yourself. That latter part is self-defense.I can and have applied my self defense skills in real life and these are skill sets that learn through training self defense.
This would be like me going to art school to study the art of drawing. I'd learn component skills of drawing - how to draw shapes, how to use shadow and light, how to use different media, and later how to express through those techniques. At no point along the way am I actually learning art - I'm learning the component skills that allow me to create a work of art, but the art only happens when I apply those skills appropriately.