I don't understand the question. What makes people use fiat currency now? Nothing. We choose to because it's the system that's already in place, plus the government expects us to pay tax on our property. Anyone can choose to live off the grid and use a barter system as long as you are tax-exempt or somehow manage to elude the IRS, you should be good haha. The problem with bartering is that it is an inefficient way of exchanging goods/services.

The more people learn of the benefits of cryptocurrency, the more popular it becomes and the more governments try to regulate it. Thing is, they really can't control it (decentralized). So they outright ban it, like what China has done.