I think a great addition to my home assistant would be a meal planning component.
It would suggest recipes from which you can choose before groceries shopping (or here in Belgium we have groceries delivery so it could order it automatically).
The amounts would be adjusted automatically to your family size and it could show the link to the recipe (or even the recipe). Using thumbs up/down it would know how often to suggest it.
I think there are a dozen more ideas here which are not explored yet. Reuse of leftovers, lunch preparation, party food planning, …
In my ideal world, this would then be visualized using https://youtu.be/qD60cBQOABY