To be fair, for anyone that has used UPI, you wonder why it can't work elsewhere.
IIRC Amazon.in also has a payment gateway that you could purchase IRCTC tickets, bus tickets etc for, which made it easy (as a Westerner) to travel around and not be too worried about money going missing / cards being skimmed. I used my (actual) credit card fewer than ten times over the course of a month.
Whether the same credit protection laws will apply, we wait to see.