You wrestle someone outside a nightclub or chip shop at 3am, chances are his mates will stomp on your head or put a knife in your back. Same with BJJ.
They are both sports, not martial arts. I've trained both for over 20 years now, yet still train my right hand sucker punch and running away technique the most.
Soon as a martial art or any form of combat develops rules, it becomes merely a sport, and moves further and further from effectiveness in the real world.
It becomes a dance between two partners who have learned the same moves, and the winner is the one who dances best that night.