IMHO, "Pure" BJJ was ORIGINALLY designed to be "street effective". Later, tournament BJJ came into vogue as a way to test technique against other BJJ brethren.
Unfortunately many schools came to focus on the sportive aspects.
There really isn't that much difference between "sport" BJJ and that which you'd use for self-defense. What I'm saying is an arm bar is an arm bar. It then comes down to a matter of awareness of what can happen. This should be addressed in training.
As for Pure BJJ being effective for self defense, I believe that it is that, especially against any other PURE style or system.
Check out the philosophies of the straight blast gym regarding this issue.
http://www.straightblastgym.com
John