I would also have a look at what people actually donate at supermarkets before criticising OP.
As far as I can see it's about 75% from "the list", 25% off list at my local Lidl. This is not a wealthy area. On the basis that lower income people donate proportionately more of their income, and we live in an area of significant deprivation by government stats, it's likely that those donating know people in need of help or have needed it themselves.
So there is lots from the standard Trussel Trust list, and always some pasta and beans and peas even when the list says no more please. They're among the cheapest items you can donate and I'm sure they'll be used eventually.
The rest includes unlisted treats like chocolate milk, sugar and instant hot drinks, foods that are popular with older people locally like beetroot, salad cream etc, a fair bit of pet food, and the odd lotion or moisturiser.
This wouldn't be an area with a large street homeless population and a lot of people who are struggling would be older. I think these donations will be appreciated. And instant lattes wouldn't stand out or shock anyone!