I was promised a $10 credit on my next order at PC Express and told to add it to the comments on the order. I did and nope, no credit. I don't use them any more because I was usually going in the store for extra stuff (or stuff they told me was out) and now they are charging on all days, so what's the point?
I guess if you have littles in the car or you know you'll be in a hurry, it's an advantage, but really, that's not me and I'd rather be sure of the freshness of my products.
As for Walmart, I've only ordered once. I got milk that was expiring the next day. I made pudding and we drank it that day, but the brand was Natrel, which is usually dated at least a month away. That means that milk sat in their store for at least a month. I was the sucker who got stuck with it. While I might have chosen it had it been the only one there, that's very different than the store using their shopping service to ensure their products are rotated on the shop floor, which is what it felt like had happened.