Why marinade meat with acid or enzymes?
Hardly a queer question.  We marinate in acidic liquids because it tastes good, really.  As Alton Brown said in the Good Eats episode, "Raising The Steaks":

"Acid doesn't tenderize meat nearly as well as enzymes.  But acids can help you tenderize your own food.  That's because acids taste tangy, and tangy tastes tell our saliva glands to do their stuff, and saliva is full of enzymes."

As that same episode shows, we generally don't marinate in enzymes, as it would turn meat to mush, and not in a good way.