Okay, time to flog a dead horse. How can we abandon the carrying of cashlike stuff around with us, and maybe free up a pocket at the same time? The credit card couldn't replace cash, so what makes anyone think you could do the same thing with a gadget?
Okay, so let's suppose there's some triple-a-rated provider who will, using some fancy hand-wavingly-great phone-integrated system, reliably (and with a receipt!) transfer cash into the hands of willing businesses. Like bank-backed PayPal, via the phone over the cloud. Yeah, buzzwords!
So here's how it would work. The business installs a bit of backoffice software which talks to said bank. You take your items to the cashier, who scans the items into the register. Or you build up your shopping cart online. Or whatever.
The "smart" cash register creates the total, stores a local transaction id, and then creates a transaction record on the cloud. A receipt is printed with a barcode, or displayed on a screen. Your phone's barcode scanner scans that barcode, and asks you to approve the transaction. And you're done.
Fully-ticketed, quick, easy, under control. Here's the process again:
-- Traditional checkout system. Scan items, build up receipt, calculate total
-- Register the transaction with the cloud
-- Cloud generates a barcode that the payer can scan to approve the transaction
-- Total time: identical to a credit card transaction.
So, given that, can we remove anything from our pockets? Conceivably, we could remove our credit and debit cards. That's two bits of plastic down, and one gadget up, so a net gain for simplicity.
But what about cash?
Yes, we could get there too. All you need is the ability to buy an anonymous line of cash from the cloud, and it's all sorted. The standard transaction model would be identified and tracked, for all sorts of good reasons including getting refunds, dealing with non-delivery of purchased goods, tax etc. But if you could buy a simple password-protected line of cash with its own unique URL, that could do it.
So, what we have is not a technical problem. It's a systems problem, which is far harder to solve...