In Bitcoin has the greatest number of benefits available to the cash - anonymity, lack of control and additional fees (which, even if they are charged by some organizations, comparable in size with the bank). His problem - the lack of universal acceptance, and such, if you will, will happen soon. Another of his drawback - high volatility, so the whole paragraph "liquidity", he is out of work.
Bitcoin or equivalent based on it, is the most likely candidate for it to eventually replace cash as a means of calculation. However, for this it is necessary to have all the fundamental features of paper money, which is now at it, objectively speaking, is no.
You can transport it and trade it physically. All that is really lacking is the ability to identify money as real money, like you can by putting a paper note up against light for instance. Maybe one could get a gadget to read public keys and verify funds in the address?