The order of things and they relative advantage of previous tech is important here. In order of appearance we had cash, swipe cards, chip cards, contactless cards, QR codes and NFC (in a usable manner). But not every country had them spread equally.
In China a large portion of the population practically skipped credit cards, when the mobile revolution came there was no NFC but QR codes were easy to implement. As a buyer you just need a camera on your phone and as a merchant you just need a piece of paper. No need for a register, no need for internet connection. In Hong Kong and Taiwan the transportation NFC card practically replaced cash and payment cards and also made NFC cards practically no better, also making QR codes relatively non-interesting. With the advent of WeChat however, this went to the side I suppose (haven't been there since so can't say for sure)
In contrast in Europe we did not use swipe cards much and went quickly to chip. Transition to contactless cards was more or less seamless because when you refreshed your card you got a contactless one. Which made merchants want to upgrade terminals. Mobile payment jut piggy backed on that. There are some shops that accept qr code payments, but with presence of Apple and Android pay, this is a massively worse use case. QR codes are marginally more convenient than credit cards, but they require almost zero specific infrastructure.
From what I understand in the US chip cards came so late that everybody just immediately skipped to Apple/Android pay. However since chip card terminals are needed for nfc, this made adoption by merchants more of a "thing". It was quite common to see "this shop now accepts apple pay" as a headline.