It's very enforceable, in a practical sense, for the majority of holders. Most people use services to exchange crypto for fiat. If you're in the EU, and use any

It's very enforceable, in a practical sense, for the majority of holders. Most people use services to exchange crypto for fiat. If you're in the EU, and use any such services, expect changes. For the people that it isn't enforceable for, they're stuck either moving countries, hodling eternally, or laundering the cash they get in return for their crypto assets.