The non-essential items are very important. My girlfriend LOVES really hot food so jars of jalapenos, habaneros, salsa, spices, etc are all in my preps. My dog and cat love treats so they're in there as well. I've even got a couple spare catnip toys and dog toys.
I rotate things into and out of the "preps" regularly. Last week our neighbor's dog came over and the latest dog toy was put to rest after a vigorous game of tug o' war. After they left I pulled out a "spare" dog toy and Abby was happy to play with the new one.
Same with salsa or the quick chocolate craving. If the GF forgets to put it on the shopping list I've usually got us covered for things that we consume regularly.
Can we survive without them? Of course, but would you if you have a choice? One can survive on beans, rice, & water but why would you want to? Preps shouldn't just be about "end of the world" they should help with your day to day life as well. Lose your job? Have a couple months of food stored up? You've just bought yourself some leeway as you find another job. Don't have time to go to the store for shaving cream? Just step over to the "preps" and it's in the pantry. Expand on what you REALLY use and you're preparing for life as you know it as well as disasters!