UK tax on crypto credit card

As in title.. There is plenty of crypto debit cards and crypto credit cards coming along... From what I found online you don't have to pay CGT on credit cards as u using credit provided based on amount of collateral u had put in I. Where purchase with debit crypto card is taxable. I can't get my head round, why it would be non taxable event, as end of month u have to pay back enough crypto to cover what u spent. If someone can explain like I'm 5 please? Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min Extra characters as 500 is min