Is the 2nd part true though? In the US sales taxes are mostly applied at the state level where the governments don't have particularly privileged access to the

Is the 2nd part true though? In the US sales taxes are mostly applied at the state level where the governments don't have particularly privileged access to the banking system and is enforced by being able to physically go to the merchant in question. Bitcoin would probably make that easier for the government as you could now track merchants sales volumes directly on the blockchain. For the federal government being able to deputize the banks to flag suspicious transactions certainly helps find tax avoidance, we've had an income tax way longer then we've had credit cards.