When traveling to China, which is also a very mobile-first country, you're expected to install AliPay and WeChat. A couple of years ago AliPay started accepting foreign bank cards, which you add to your account (in addition to lots of other information including photos of yourself and scans of your government id), and then pay through the AliPay application everywhere. Cash has been made extremely inconvenient or even impossible to use, foreign cards are also often not accepted.