During my last trip to China, I went to a bar with a friend in Beijing and I tried to pay with cash and the person looked so confused. They were probably thinking "... is this?" and then they told me that they didn't carry any cash to make change for the 300 RMB for the 253 RMB bill. I ended up paying 200 in cash and my friend used their WeChat to pay for the rest of it. Very annoying.