I believe this is not really useful if you do not have a mainland China bank card. A few users have tried before.
I believe this is actually for foreigners living in China. They still need to get a mainland bank card to use WeChat Pay.
But it is not totally useless either if you add a Singapore credit card. It is said to be useful with some limited WeChat partners like DiDi and Ctrip and Aur China and China Railway.
Ref:
http://www.chinadaily.com.cn/m/beijing/zhongguancun/2019-01/09/content_37425026.htm
How can foreigners use WeChat Pay?
( chinadaily.com.cn )
Updated: 2019-01-09
At present, WeChat Pay covers more than 300 banks, and supports several overseas credit cards, including JCB, VISA and Mastercard, which means Tencent users will have two mobile payment options.
The first is for users who have a mainland bank card. At present, WeChat Pay and Tenpay support the binding of the savings cards and credit cards of more than 70 banks by using mainland residents' ID cards, passports, Mainland Travel Permit for Hong Kong and Macao Residents, and Mainland Travel Permit for Taiwan Residents. With any of the above documents and a bank card within the support range, users can easily open WeChat Pay for online and offline consumption.
The second is for users who don't have mainland bank cards. By binding Visa, Mastercard or JCB credit card through regular card-binding methods, users who don't have mainland bank cards can use WeChat Pay in WeChat Wallet's merchants and cooperative brands in e-commerce, O2O, travel, trip, including JDcom, Ctrip, Qunar, Didi, Air China, China Railway Corporation (12306).