How would your example with the HMRS be different with bitcoin? They know you have it, they invent some tax on BTC holdings and there you go.
BTC is a surveillance nightmare. This is why the states allow it.
Discussion
But less of a nightmare that the current system. But using lightening and e cash help with this. I’ve never used Monero, but I hear that too isn’t perfect.
In the current system, the bank and the government can know your balance and transactions.
In BTC, it is everybody in the whole world.