Until we have developed artificial general intelligence, I wouldn't trust a computer to recommend a cheese to with a certain kind of crackers. In stores with a reasonably wide selection of goods, I usually have to ask for the location of at least one thing.
Although locating stuff _could_ be solved by looking it up with an app, I would rather pay the markup. And I'm quite certain that a lot of other people will, because as opposed to with a lot of other goods, you're often low on time when shopping for groceries. I guess the urgency of shopping is why online grocery shopping hasn't taken off as much as even I would have predicted a few years ago.