One reason for Uber's success is that it removed the friction and pain of paying for a taxi. However a service that requires a mobile phone and credit card doesn't work for the under and unbanked. In emerging markets where cash is king, Uber has realized that there is still great utility in the ability to use a cellphones to hail a cab. Uber created a cash option for these markets. This new cash option is now available in 10 markets, but will expand to others where credit cards are not as ubiquitous.