‘De facto’ means roughly ‘in actual practice’ or ‘effectively’, whereas ‘de jure’ means ‘explicitly spelled out in the letter of the law, the orders of a judge, etc.’

If there is a law that says ‘cryptocurrencies are all banned’, but there are no penalties for using or holding them, no enforcement agency in charge of finding and prosecuting cryptocurrency users…

Then crypto is ‘de jure’ illegal, but it is ‘de facto’ legal.

Like, we have lots and lots of tax laws, but the IRS basically never enforces all the relevant ones against very wealthy people.

Thus, for very wealthy people, much tax evasion and many forms of fraud are ‘de facto’ legal, despite being ‘de jure’ illegal.