The largest problem I have with cryptocurrencies isn't the concept but the practical market reality of with whom they are competing: governments and central ban

The largest problem I have with cryptocurrencies isn't the concept but the practical market reality of with whom they are competing: governments and central banks. Heads of State have been killed for trying to achieve what Bitcoin aims to achieve. If it -- or any other cryptocurrency -- ever truly threatened to replace the petro-dollar I suspect some very shady and aggressive things would happen, culminating with criminalization of exchanging that crypto for goods, services, or fiat currency.