Like many foreigners living in China, I have fully transitioned to using digital payments through apps like WeChat or AliPay. Naturally, AirBnB also accepts these payment options...as long as you're a Chinese citizen. I don't think this issue is caused entirely by AirBnB. After all, it is AliPay's and WeChat's policy to only allow citizens to purchase from overseas vendors (I do think their parent companies should change that policy), and AirBnB does let users choose a debit/credit card as payment options...but (there's always a but) none of the payment processors are common in China. If you're a foreigner living in China, chances are you don't have a Chinese credit card, and your debit card will most likely be a UnionPay card, not Visa or MasterCard. This means that, in order to book a listing, I'd need to move funds between bank accounts in different countries, which is a convoluted process that could be made easier if 1) AirBnB accepted UnionPay and/or 2) AirBnB accepted PayPal in China.
