Depends where you live. In many places in Europe people shop for 1/2/3 days only because of the close proximity to the shops.
This is also my experience for folks that live in NY.
That said, I also have no use for 15 minute grocery delivery because of this. And it seems like it would only work in urban/inner suburban areas; it's not going to be practical to provide this sort of service in outer suburbs/exurbs, and they're the only ones who'd have a use for it.