Imagine the situation in which we don't have any physical money and every currency is digitalized. The US dollar is now a token, the Japanese Yen is only in the network and the British pound is a fast-moving digital coin. What are the consequences of such an economy for the poorest of the population? Do you think that a few people can influence the digital wealth of people and wouldn't hackers be the best people to have as friends?
Well, as for nowadays. What's keeping robbers from the bank robbery in order to get a cash? Even if it happened now, who would be suffer the loses? Similarly, in your future. Hackers will steal a certain amount of DIGITAL money. So what?