And while Amazon is stuck with maintaining both computer and physical infrastructure, Google will have effectively offloaded the physical infrastructure to the free market. Not only that, but while Amazon must seek economies of scale and efficiency at every point of the distribution network, Google can leverage the irrationality and inefficiency inherent in a distribution network composed of individual retail outlets. In the same way that eBay doesn't have to worry about packing up and shipping millions of disparate items, it just takes a fee off the top for delivering the sale.
I wonder about the benefits versus the costs to stores. Though you can already walk into a retail store and Google up an item on your phone to see if it's cheaper somewhere else... and you can already search for reviews of an item online, etc. I guess what is interesting here is that Google is delivering the physicality of a store to your screen; so conceivably some walk-ins that might have occurred just to check a place out will now occur online. On the flip side, turning every retail outlet into a 24 hour business has got to have some appeal.
Going really crazy with this, looking ahead to Google's driverless cars getting approval to run without a safety driver on board, you could Store View to your favorite cafe, put in your order for the caffeinated beverage of your choice, have the Google car drop by, the barista puts the drinks in a carrier in the back seat, the car picks up some Chinese food, energy bars, and a pair of earphones for you on the way back, you get a text telling you to go outside to pick everything up, you scan your GoogleID into the car, get your stuff, head back into the office and prepare to code all night. If you are so inclined, you drop a few bucks into the online tip jars of the coffee shop and restaurant. Based on your tip ratio, the star rating of the establishments in question are bumped up ever so slightly.
Google has the computers, cameras, and cars to take over the world of running errands.