One important factor is the Chinese government view cash as necessary evil. They prefer the money to be in the digital form to avoid issues such as grey economy

One important factor is the Chinese government view cash as necessary evil. They prefer the money to be in the digital form to avoid issues such as grey economy and difficulty in collecting tax. As such they refuse to issue large denomination cash bills. The largest RMB bill is only 100, which is about 13 USD. It was first issued in 1988, when the nominal GDP was only about 2% of the current size. Obviously this makes large transaction in cash difficulty. Thus created an opening for alipay and wechat.