If you tell it you want more coffee, it should know what you like and suggest a mixture of brands you bought before and new ones you may enjoy. If you tell it you're hungry, depending on the time of day it could suggest you some takeaway you've ordered previously or something else you may like. If you say the same some other time it may suggest recipes based on what you have at home or it may suggest nearby restaurants. It should keep track of your friends and otherwise and tell you when their birthdays are coming and it would be nice if it could even suggest some presents based on things you've told the assistant before, or their wishlist on amazon or something else.
There are a lot of things assistants could do, but it needs to know you. The model where everyone has the same assistant doesn't quite work out.