Thus they resorted to QR codes, which are now promoted as something modern etc. in these propaganda pieces similar to WeChat propaganda (which usually fail to mention that pretty much all int competitors were blocked or would be blocked if they would start gaining any traction + your wall posts and even private messages are censored if they contain sensitive keywords, of course no encryption, no SMS, etc).
Meanwhile in west I am pretty much forgetting my PIN because I can pay almost everywhere with wireless debit card just by touching terminal without preparing some application in mobile which must be charged, entering PIN code to unlock app, scanning/providing QR code and confirming, soo convenient those QR codes... And lets not forget if there are people in front of you who are just preparing when they should be already paying, which makes everything slower than cash (real life experience from China).
Was living in China for years, you can consider Wechat payments convenient only if you are Chinese who never used contactless bank card like Visa Paywave/MC Paypass available at majority of shops.
Plus on top of this these mobile payments are widespread because chinese online banking is horrific and you can't use it on computer without installing certificates, special USB dongle, etc. while in west it just works in browser without anything.