Take a self-driving car to Walmart?

So, you order your groceries on Walmart.com, and while your grocery order is being prepared a self-driving car picks you up and takes to Walmart. Then you get handed your groceries, and a self-driving car drives you back.

Here's the story:
https://medium.com/waymo/growing-waymos-partnerships-in-metro-phoenix-965941451902

But what do I need to do for them to just put the groceries in a self-driving car and send them to me? It would be one less trip by the car and certainly a better experience for me, the shopper.

I totally get it that program is trying to get people to be comfortable actually sitting in self-driving cars, but this would just annoy me. It's only marginally more efficient for the users and it's needlessly adding to car traffic instead of reducing it, which it could be.

I'm much more fond of the idea where they drive me to the mall and I don't have to navigate the parking lot. But in general, I'm concerned that we're pushing the idea of individual self-driving cars much too hard when we should focus on innovations that could possibly reduce traffic.