Aside from hardship preparation, the main reason to stockpile is to get good deals, and then having enough to make it through to another good deal, maybe longer. If you are looking to stockpile simply to pay off debt, you would be better off paying extra on the debt now. The amount you're putting towards the debt won't be any different, just the month you are paying extra. Assuming your debt is counting up interest, the longer you wait to make payments, the more you are going to pay in the long run.
Now, the money you save by stockpiling items at lower-than-normal prices can certainly be put towards your debt, benefiting you in multiple places.
There does come a point, though, where the money you are saving by stockpiling isn't offsetting the amount you are paying extra towards interest. For example; the people who thought it was wise to stock up on Forever Stamps, because the price was going to be going up a few cents. That's hardly a good investment, especially if you are paying interest on debt elsewhere.