You don't need "AI" for that. All you would need is some standardized APIs for the various shops, and you could easily solve this with computer technology from 20 years ago.
It's not that there's no API. It's that there's probably a different API for every single grocery store. And they make random changes and don't have public documentation. That's why we need the AI.
Indeed. LLMs read with the same sort of comprehension that humans have, so if a supermarket makes their website compatible with humans then it's also compatible with LLMs. We have the same "API", as it were.