I think partly because Google and Apple controlled the contactless bits of the phones for many years, the non-OS-makers like WeChat and AliPay made use of the open technology of QR codes. I think theoretically you could build equivalent things as they have with NFC today on those platforms but on the other hand being able to set up a “POS” with nothing more than a printer does have an appeal to it, even if writable nfc stickers cost 5 cents you still have to go buy some.

QR payments in china was already prevasive before contactless payments became prevasive in the west. And as others say: not all phones supported nfc at the time. Remember iBeacons on iP5? Wechat and Alipay was already everywhere by then

It's all WeChat Pay (or AliPay).

Lots of phones don't have NFC. All phones have cameras.

Having been there recently, it's about as annoying as taking out your phone to pay for something. Some systems also support NFC now, though the most common is still QR. Also helps that their QR scanning tech/transaction processing is really fast, many transactions were as fast or even faster than me scanning with a card from my experience.

(Also if you want to talk annoying payments don't get me started on how insane it is that the US still requires me to hand over a physical card at most restaurants to take over to their register... sorry I just can't help but get annoyed by this lol)