> But I don't understand why so many restaurants still hang on to it.
In some Chinese cities you can walk all day without finding a restaurant/shop that can give you change if you try to pay with cash or that accepts your western credit card.
Without Alipay/WeChat you will be stuck in your hotel unable to do anything.
However unlike the crappy western solution, where each business wants to have their own app, the experience is extremely smooth: Scan a QR code with WeChat, the menu opens in the app, order, pay.
Want a bottle of water in a small shop? Grab it from the cooler, scan the QR code on the cooler, type in 2 CNY and hit send money. Cashier gets a ding that you paid 2 CNY. Confirm with a nod and just leave.
Ride hailing (Didi - which ate Uber's lunch here), airplane&train tickets, and much more is also done right through WeChat/Alipay.