I just got a $45 discount for paying cash. The credit card machine was down at this particular spot - one where many people with the means and/or inclination drop hundreds of dollars, but I a good deal less - and the guy wanted the sale. He estimated that he was down a thousand because he couldn't accept cards - he didn't even have one of those ol' cha-chink carbon card sliders to manually process plastic. He was just, basically, helpless. Credit card processesing led us into the Cloud, and it still gets lost up there, as all else (documents, phone numbers, friendships) inevitably will.
Of course, I hustled off to an ATM to get the cash I needed, as there would rarely come a circumstance that would have me carrying more than $20 on me. Hitting up the cloud for money on my friend's behalf got me a nice tip for my trouble, and worked out for him too.
Somebody will need to get paid to convert the paper back into sky-friendly bytes, too.
There are, and will be for a while I imagine, margains to slurp off when digital and real are forced to pretend they are the same thing.