Could crypto-currency change how we pay?
Although we feel we know cash intimately, let's take a deeper look at some of its attributes. First of all, it's represented by a physical object: either a banknote or a coin.
If you buy something, you hand over that physical thing to the seller. It leaves your possession and enters theirs. Your net cash worth is reduced by the amount of cash you've handed over.
Second, it's relatively hard to clone your cash. It would be nice if you could just photocopy banknotes - well, at least it would be until everyone started doing it and the global economy crashed a few seconds later - or you could stamp coins more cheaply than you could buy them, but there are various protections to make sure that this is inefficient and costly.