Its merely a traditional means of dispatching the beast.
Chickens and rabbits were (And the best still are) bled and drawn and hung for a day or more to create enzymatic reactions (controlled ROT)
Seafoods like crabs , lobsters and shellfish cannot be killed and held for later.They must be killed by the cooking or immediately before cooking. Its hard stabbing a lobster in the brain, AND don't even talk to me about a clam.
Imagine stabbing ten thousand crayfish in the basal cranial area. Itd take one a week to cook up a "bug boil"