Being an influence of Keynes is nothing to be proud of, on the contrary. They would be worthless because there would be no demand for them, regardless of their number. But please, prove me wrong.
you are already proven wrong.
currencies are accepted today even though there is inflation.
built-in devaluation as is proposed here is just an "honest" form of inflation, i.e. you don't see the value of your money decrease, but you actually see your money decrease.
there isnt much difference, acceptance-wise.