I don't see it as a class thing but it certainly is a culture thing. When the American's go to build their app, you get something out of silicon valley that is almost built for the programmers. It will use hardware that requires everyone to buy a new phone (like NFC). Things like QR codes would be derided as insecure and exploitable. It will comply with consumer protections.

In China the app will be made chabudao (good enough). It will use QR codes because its fast and its what your coder knows and its whats on everyones phone. Security exploit? Shenme? Consumer protections? How do I say "caveat emptor" in Chinese?

There's something to be said for the Chinese approach. By making something stupid, they've made something smart. Not all innovation requires technical accomplishment.

Edit: after thought. Credit where its due to alipay and wechat. The QR-code works even when my phone is temporarily without a connection. I don't know what goes on in the background, but it def saved me a few times from looking like an idiot with no way to pay for something.

Another point about dumb being smart. Alipay does have a sound based transaction system (like what crinkle tried to do). AFAIK no one ever uses it. The plain old dumb QR code is faster and better understood and is therefore better.