When you use a credit or debit card to buy a sandwich, you don't pay any tax on the transaction except maybe sales tax, but cryptocurrency is different.
source https://www.google.com/url?rct=j&sa=t&url=https://tax.findlaw.com/federal-taxes/cryptocurrency-taxes-and-regulations.html&ct=ga&cd=CAIyGmM2Nzk3ODA2ZWViNjVjODI6Y29tOmVuOlVT&usg=AFQjCNHRvv6yPgRQNi0Rjr-ZC0gZr-KI9g
