Rewards credit cards are everywhere and Americans love them. About 90% of all credit card spending is on rewards cards. That's, of course, because the more you spend, the more you get in perks. In 2019, consumers received about $35 billion in rewards. But how are banks paying for all these perks? Some economists claim there's an annual redistribution of more than $15 billion from less to more educated, poorer to richer and high- to low-minority areas, widening existing disparities.