Crypto currency will not and will never replace real money. Why? Because not every single person in this world are literate on high technological things and ideas and not every person in this world can afford to buy a computer or a smart phone and pay for internet bills. Do you think that the homeless people benefit if real money will never exist anymore? Yes they can earn a small amount of cash from begging or doing some tasks or what ever they do. If you get what I mean. 
Yeap i agree with you and would like to add. That all cryptocurrencies at the moment is like forex trading obligations and they dont have any possobility to replace real money. But can they replace companies that have obligations? I think yes.