Yes, UPI works. But it's a terrible system for privacy and autonomy. It has so many intermediaries, requires phone number and linked to person's identity. It should not be called a peer-to-peer payment system in anyway. It is controlled by the government rather than Visa or Mastercard. That's the only the difference.
Sure, but visa and mastercard share their transactions with the US government (among others).
"Hot Watch": where the US gov gets real time surveillance on a target.
Bank Secrecy Act: where private networks and their issuing banks are legally mandated to act as unpaid deputies for the state.
At least with UPI you're sharing with less governments?