If one is using a Mac with the Safari browser, the Walmart website is spotty at best and useless most of the time.
Now, before the Apple-bashers jump in, Amazon works perfectly with Safari, and Walmart turning away a significant fraction of their customers through incompatible website design is just plan stupid.
OTOH it is an interesting business model -- shipping to distribution centers for customer pickup. If the shipments can piggyback on normal Walmart delivery trucks I can see a savings. The other savings comes from substituting low-price in-store labor for much more costly individual delivery drivers. Of course, as a consumer, they are going to have to offer a significant discount to get me to drive to their store and wade through the "people of Walmart" I find there.
It seems to me it combines the delayed gratification of on-line buying with the negatives of driving to the store and standing in line. Now if I can select from in-stock merchandise at internet prices and get the immediate delivery this would bring, that would be a plus...