I respectfully disagree. BJJ is a ring discipline. Its emphasis on purposely taking a fight to the ground is a tremendously dangerous one in the real world where the opponent might have friends on the scene to help him out.
Make no mistake, once on the ground, you have to have an idea of what to do when you get there, but in a real fight the ground is the last place you want to spend any time, let alone on purpose.
BJJ, and judo, ju-jitsu, wraslin' etc., by themselves are not a complete answer to unarmed self defense. You need some sort of striking ability while on your feet because you can better make out the developing larger situation, even if poorly, or break contact while on your feet. You can do neither while trying to pretzel someone. The first indication that the bad guy has friends could very well be a boot to your ribs while you were "winning" on the ground.
What's amusing to me is that most of the KOs on crowdog's video rely upon Muay Thai techniques. However, even MT needs a ground compliment that the art mostly lacks.