also, in the absence of refrigeration, the pepper chemistry extends the life of the food. Loads of bacteria cannot hack it neither.
Garlic was probably popular back then too for similar reasons. Salt brine was probably used as a preservative as well.
So they used the peppers the way middle easterners used salt. I wonder if they had access to much salt.
Tastes good. . . and is good for you. So the 2-week-old tamal in my fridge is still good, eh?