First, it is good Netiquette to use a credit or debit card. So, don’t use cash, money orders, or wire transfers for online transactions. Given, non refundable.
Currency Netiquette Ecommerce
Next, credit and debit card transactions are electronic. Then, e-commerce. Thus, Internet provides a means of transmission for e-commerce.
It follows, credit and debit cards use the same means of transmission. Therefore, compatible. And so, transactions are easily processed. Also, accounted for in online statements.
Card issuers, banks, hold merchants accountable for merchandise sold. If it is defective the bank will handle a dispute for you. This layer of protection for internet transactions is not available with cash or wire transfer.
Use a credit or debit card because cards provide accounting and recourse for transactions.