This topic is from 2020, but it does not lose validity, OP's explanation seems somewhat "rigged" to me to arrive at the idea of Legal.
Come on, I just had a discussion on the subject and the first thing to do is define legal in each country, from there, we can interpret that "legal" does not mean that you can carry out purchase and sale transactions of any good, in In my case, it can be done p2p, use it for whoever accepts it for payments, etc.
But for the formality of a purchase and sale, a legal document that allows me to deduct taxes does not work, even if it is legal, that is, I must sell it and then justify my funds, not because I sold them they are already legal, the money product of That sale in my Fiat currency is the legal formal payment.