Interesting guy, good link thank you. And you're right, self defense oriented people won't be the best competition guys but they can do very well. Actually, 80's and 90's BJJ competition looked more like the self defense approach than what we see in competition today.
He gives a good explanation of the art in this video. BJJ traditionally has some weaknesses though they are improving with exposure to other arts through mma (due to tradition and competition rules for example very few leg locks and neck cranks till black belt and even then you can't do certain things) but boy does it make you good on bottom and teach leverage and technique and patience over muscle and forcing things quickly. And that translates to both self defense and competition. The core concepts are the same really.
Member of DaJoGen MMA school under Dave Hagen and Team Chaos fight team under Denver Mangiyatan and Chris Toquero, ran out of Zanshin Martial Arts in Salem Oregon:,