The card isn't limited to Amazon, either. You can use it at other online stores, or to take advantage of outside internet services like Netflix, Spotify and Uber. Physical card owners can shop in retail stores. And if you need cash in a pinch, you can withdraw it from ATMs.
As with Amazon Cash and similar efforts, there's one clear objective: making Amazon accessible to a wider swath of the population. Under a third of Mexican adults have credit cards, according to the government's latest report, and that greatly limits their ability to shop through websites that frequently insist on credit. Rechargeable theoretically lets many more people buy from Amazon -- and since it's relatively open, gives them much more overall purchasing power.