If you use a rewards credit card, you're more like a millionaire than you may think. Although most adults have credit cards, millionaires are even more likely to use them. According to the Federal Reserve, almost all adults with incomes over $100,000 have a credit card in their name. But if millionaires are so wealthy, why do they rely on credit? Credit cards provide plenty of benefits, even for the super-wealthy. However, you don’t need a seven-figure net worth to take advantage of those benefits. Dig de ...