BJJ is such a meme. If you do it for it's own sake ie building a discipline, hobby, and sense of brotherhood, that's great. But it's worthless for a street fight. The last place you wanna be in a fight is on the ground, you'll scrape all your skin off on the pavement and worse, one of their boys might come in and kick your skull in. It's such a joke. People forget how real fights work. You want to end a fight ASAP (ie haymaker to the head) then split, not scuffle around on the floor like an autist for several minutes.
The same things can be said about mma. That was my biggest takeaway lesson from it, how different it is from real. The cage is like a padded room for crazy people. The floor is made of boards that flex and multiple layers of mat. A slam that would be life ending on pavement is worthless...you just bounce and it doesn't hurt at all.
Padded gloves are a big difference that benefits the wearer. If I ever got into a bar fight, I'm fairly certain I could break the hands of some guy trying to punch me by throwing elbows. It would be hilarious. "Officer, that guy punched me, but hurt his hand and started crying." Then he gets a battery charge and an expensive orthopedic surgery.
My trainer had a Japanese jiu jitsu background. A lot of it was against mma rules, because it works too well, lots of dirty tricks. There's no pulling guard. Mount position is shin on opponents belly, with the other foot on the ground. I've seen cops use it on the street.