Dead things rot. This makes them less palatable.
Before Mr. Frigidaire came along, a popular solution to this problem was to bury the dead thing until you were ready to eat it.
Thus we got narezushi, the original form of sushi. Bury the fish with rice, various bacteria get going, and eventually you have a pasty fish/rice substance described as having “notes of vinegar, butter, and cheese.”
Thus too we got the first gravlax, which means “buried salmon”. Heavily salted fish in a barrel – that was an accepted preservation method. Not enough salt or barrels? Salt the fish lightly, wrap it in bark, and dig a hole = gravlax.
Ancient bog butter is still uncovered on occasion in Ireland. They buried the barrels partly to preserve and partly to hide it from roving brigands.
The Cherokees did it. Various peoples in Africa still do. Eskimos do or did (but that’s cheating since it’s so cold anyway).
Andrew Zimmern says between buried meat and buried vegetables, the vegetables get much nastier.
I’m just going to take his word for it.