Everybody has a cellphone. You pay and receive "money" with your cellphone. Wallets will be redundant in the future, everything that is in your wallet will be stored in your phone.
And you know which currency can be paid with your phone? Exactly!
And if I have to buy something, I will just trade in my value stored with the thing I want to buy. I don't see any need to go to an intermediate thing that keeps decreasing in value.
Paper money was preferred over gold because it was inconvenient to keep working with gold, not because the paper loses its value.
Bitcoin may be good to store value (gold or land being the best), but isn't adapted for exchange, as no one wants to use it to buy something. Sellers should offer steep discount for the opportunity cost in order to obtain the money, which isn't very likely.