-- EDIT -- I'm curious about others' grocery buying habits because I don't use Instacart.
(I do use a particular delivery service that has direct relationships with farmers, so that could partially explain why it's so cheap.)
In contrast, in Brooklyn, they won't even let you bring the shopping cart into the parking lot. But then again, just about everyone I knew in Brooklyn had one of those pull carts and just used that to shop / carry their groceries home. That said, I generally chose FreshDirect over dragging my own groceries around once FD finally came to Bushwick.
The person delivering food may be able to use different mechanisms (e.g. vehicles) or division of labor (teamwork) that are not practical for the recipient.
> I'd just go out to eat at that point.
This is not always practical or desirable for lots of people: the sick, those with young kids, the infirm, etc.