Well, that's the problem.
If the digital currency doesn't have any significantly attractive qualities outside its use as a store of value, it's a shitty currency.
If you can make a currency that people will use on a day to day basis, voluntarily, despite having 4% inflation (which is a much better target, economically -- the 2% is the weaksauce compromise with the anti-inflationists), then you've created something which has real utility.
