> I said, "an instant ramen cup, but not the cheapest brand. Also, watch out because they sometimes have beef broth and I'm allergic."
This strikes at the heart of the issue. The criteria you’ve placed on the ramen is actually pretty complicated, and yet it is simpler than the criteria many use to select produce, dairy, and meat. Needing to meticulously articulate criteria for the 100+ items purchased every month would be a pain. Items also have interdependencies, e.g. I can only afford the fancy yogurt if I got a deal on something else, and context dependent, e.g. I want to spend more on chicken for the fancy dinner, and less for a weeknight meal.
Of course, these criteria are theoretically learnable by an LLM, but extracting the prerequisite information is hard. So much context exists in your mind. For instance, just looking at your ramen purchase history, do buy chicken ramen over beef ramen because you like chicken better, or is it because you actively dislike beef? It’s hard to say without your explicit input. If every purchasing decision requires explicit input, it seems better to cut out the LLM.