Have you tried the app in question? Even with the low quality cameras on the first Androids, it worked really well. On my 8MP camera now, it's insanely fast. And since everyone would be doing it as they picked things up, the lines to check out will be limited to making sure people didn't steal.
Having said all that, I think elimination of the traditional supermarket is more in line with what I want in the future. There was a startup on here that talked about having no customer-accessible store. The customer orders from home, drives up in their car, the store loads the order in the car and collects the money, and the customer drives home. Eliminating the customer's driving is a logistical nightmare, but I expect that will eventually be solved, too.
Have you tried the app No I haven't - I've just used the 'standard' Android barcode scanner. So now I feel a bit sheepish given that I may have over-egged the pudding with that little scenario!
I've used internet supermarket shopping in the past, when I didn't own a car. It was reasonably good, and you paid £5 for delivery within a 2 hour window. You would tend to sometimes accidentally buy a weird size of some item though.
Having said all that, I think elimination of the traditional supermarket is more in line with what I want in the future. There was a startup on here that talked about having no customer-accessible store. The customer orders from home, drives up in their car, the store loads the order in the car and collects the money, and the customer drives home. Eliminating the customer's driving is a logistical nightmare, but I expect that will eventually be solved, too.