I think the primary reason is a loss of privacy and freedom. With a digital currency all your purchases can be tracked. You also lose freedom in that government

I think the primary reason is a loss of privacy and freedom. With a digital currency all your purchases can be tracked. You also lose freedom in that government at any level could suddenly make some products or service illegal, throw in that they could retroactively do so. Of course there is monetary policy too. Negative interest rates try to force spending to correct bad government policies which usually are the cause of depressed spending. Then combine this with the idea that printing digital currency is as simply as flicking a switch which would rapidly devalue currency in people's accounts. Simply put, its another attack on privacy and the freedom it entails