Either the food is cheap enough to not care about the duration enough to zone 4 times to use it, or it lasts so long that you (or someone you used your stewpot in this example) are going to die at some point in that completely overkill 8h duration.
Having your food buff wiped on death is a dealbreaker when considering using more expensive food more often than not, and on that note, changing that "mechanic" would see suggestions like this thread be more widely-used, as you could pop into Reisenjima and use a stewpot on your friends and you're good for your marathon night...while bankrupting the chefs of Vana'diel.
I try not to die, and tend to expect that I won't. Even in high-end content, I'm generally among those that don't die. If I do, it's usually something close to a wipe. That said, giving a party of 6 top-notch food effects for 8 hours is nice right before doing multiple Omen runs. I'm now using Altana's Repast/+1/+2, so the benefit to pet jobs increases the value.