The main issue governments dont let BTC and crypto to grow too out of hand is because of how hard it is to regulate it. If they can set a standard way all over the world to regulate crypto, they would let it grow.
When i mean regulate, i am referring to two main ideas: Volatility and Security
Volatility:
- how will they control the price if they do not control the supply
- how will banks have any control in terms of rates of exchange / growth of value
Security:
- How to prevent use in black market (KYC and AML is something
Korea is looking into with their recent changes)
- wallet security vs bank accounts, a lot less secure