I think its interesting, thats all
I never got in lots of street fights but when I did occasionally I could hold my own and I was usually on top. I think its interesting, besides even if I know how to fight before taking martial arts, would i know how to put an armbar a good kick to the leg etc.. how to unarm an armed attacker. Maybe I can but martial arts just makes sure you can. I think its something special, just put someone who "knows" how to fight and dosen't take any martial arts against any1 and put an experienced martial artist. You take less hits and you end the fight more quickly. And I also like sport martial arts, no1 can know absolutely everything about martial arts before he starts training no matter how much he "knew" how to fight.
Overall its a good source of fitness, confidence, a possiblity to meet new people while training and self defense. So many possibilities.