PoS systems in Germany are already linked with the IRS today. If purchase something under the counter with BTC it will be missing from the stock (for example). If you send CBDC to another person both sides will have to justify the whys or risk having their funds frozen. If you send €50 to your daughters phone for her birthday, tax will be deducted from the transaction. If you want to acquire BTC you'll have to do so through a licensed exchange - if you have permission to engage with such a business (might be blocked in your currency). Etc etc etc my friend.