Implementation of such a system of control over humanity is very convenient for the world government, because if you leave only one digital currency, you can not only track all transactions, but also prohibit the use of the system to an undesirable person.

Just imagine that we will all someday have a chip containing all the information about us, our movements and all our money. Let's say if my actions are not liked by the government all the funds on my family's chips will be canceled and we just can't buy food in the store. This could indeed become digital slavery and total control over a person's will and thought.