It's even worse than that. Not only can MasterCard arbitrarily refuse to accept payments for a business, it can cancel any consumer's account with little recourse. Let's say that someone steals my credit card number and uses it in a foreign country, and MasterCard detects this fraudulent use of my card and shuts down my account. At that point, if I can't buy food and other essentials with cash, I'd be in real trouble. Also, it's hard to get a credit or debit card if you're unemployed - if you have no income and/or no credit history, credit card companies and banks don't really want to do business with you. And if you're homeless and begging for money on the street, nobody is going to lend you their credit card.