[bsder]

The entrenched monopolies have been actively fighting allowing use of your phone for universal payment. Visa/Mastercard/et al. (rightly, in my opinion) view that as an existential threat.

This is the real reason that we can't do this on phones in the West.

[seanmcdirmid]

The real reason we simply don't need to do it in the west, while in china you don't have any other option accept to just use cash if you want to buy from the local wet market or pay your didi driver.