BTC can be convicted and frozen. The court issues a judgment to miners and master nodes to freeze a certain black money address. The master nodes and miners will execute it and put the criminal BTC on the freeze list. Transfer transactions submitted by the criminal address will be rejected. Other virtual currencies such as U can also be convicted and frozen. In this way, it is better to use cash than to store black money with virtual currency. Cash can be stored physically instead of in banks, but virtual currency cannot leave the blockchain storage. No matter how the black money is transferred, it has nowhere to hide.