Per some people, LLMs of the future can do literally anything that's possible to do. They could create quantum computers powered by fusion power.
That has nothing to do with the question being asked, can you rely on an LLM today to help you track carbs as a diabetic?
This is very explicitly what the article is all about. Potential future LLMs are entirely irrelevant.
This isn't something so fanciful as fusion power, this is reasonably something that might be within the capabilities of object detection transformers. Whether a different prompt/finetuning with a good dataset could make this work is very relevant here.