That's not really true. Electronic money functions as long as people think it has value. It's perfectly conceivable that people will find digital tokens to be valuable. Especially if it's verifiable by a third party, such as in a Bitcoin-like system.
Bitcoin already has an exchange value and some use beyond its function as money, but most people do not accept Bitcoin as money. In fact, I would say that many Bitcoin owners do not own it for monetary purposes but as an investment/speculation vehicle.
But this is still a counterexample. Many people who hold it (including myself) do use it as money. It started off with *no* market rate. Now it has a market rate to the point where people are willing to *use* it as a unit of value.
Demand for a good arises from its perceived benefit. The benefit money offers is its purchasing power (its price in terms of goods and services) - for something to become a money it must have a pre-existing purchasing power, a price which could only have emerged if it already had an exchange value.
This would not work because electronic money is merely a device of storing information concerning debits and credits - it cannot acquire any independent purchasing power and thus cannot become money itself.
The main indicators of economic growth, or 'how well the economy is doing', do not usually analyse the distribution of wealth; specifically, periods of runaway growth often come out of the pockets and paychecks of the working class.
The interest rate works as an indicator. Falsifying this indicator leads to a misallocation of real wealth which in turn weakens the process of wealth generation and the ability of businesses to grow and thus is a detriment to the economy as a whole.
Economic growth is an increase in the production of final goods and services. This can only be achieved by enhancing the infrastructure that enables lifting the production of goods and services (misallocating weal wealth weakens the wealth generation process and thus the ability to enhance it).