We've already heard many different central banks voicing the same position, they are so used to controlling their country's currency and working with currencies of other nations that they can't just accept the reality that currency is a social phenomenon that can spontaneously emerge when many people decide to use it. It's almost like they are trying to convince people that government is the source of money and the whole economy wouldn't exist without it. But the fact that Bitcoin has got such a huge popularity demonstrates that there are people who don't buy the lies of central banks and understand how the economics actually work.
Just a speculation, I believe that they see cryptocurrencies as a 'threat' to the country's regulatory power. Being a decentralized currency means that no government department or institution can regulate its transactions. In the case of South Africa, they call it 'token' rather as a 'currency' but the function remains the same. People would utilize it as a form of currency (which eliminates the peer-to-peer transaction) and some would acquire more for investment purposes.
The popularity of bitcoin can be seen on its price and revolutionary platform technology. People would use bitcoin as an instrument of an investment since its volatility calls for short-term yielding of income with high returns. Funny thing is, most people that invest into cryptocurrencies are also individuals who are clueless about its background and nature. They seem to overlook its volatile function, which explains on why most of them are confused whenever the prices decrease.
