Can you show me a practice where a tourist would be held accountable under the law for paying with cryptocurrency?
In Russia, it is also prohibited to pay with cryptocurrency, by law, you have to sell the coins for rubles and pay. But no one cares about it.
In Russia do you have merchants who openly accept payment in cryptocurrency? Despite it being prohibited. I don't live in Thailand, but the article reads that tourists have to convert cryptocurrency to Thai Baht for spending, i don't know if this is strictly monitored or if nobody cares about it like you say happens in Russia.