The trade off for privacy is for growth and usage, just like WhatsApp. Eventually both will have privacy features built in down the line so this will be a solved problem, just like now that WA has E2E encryption, I see the same for UPI.
Crypto had 16 years to reach the amount of people that UPI has reached and what does it have to show for it? You talk about privacy whereas the majority of cryptocurrencies are not privacy friendly and even if a tiny minority are, the exchanges have (rightly) banned them and require KYC to trade them, making this 'privacy coin theater' pointless.
Either way, the third world have technologically superior payment systems than the US, at least in a few months when FedNow comes around, which is yet another reason not to use crypto.
> Kiran Jonnalagadda, a technologist...
Of course it's always the 'technologists', I am afraid 1 person is not a good sample size, but to entertain this anecdote:
You have heard of a disposable / prepaid SIM card right?, you can get one down the road and you're ready to go with UPI again.
So what is your proposed solution? All I can see with crypto is a complete Rube-Goldberg contraption of a system that is good at losing people's money. If your solution is another privacy pump and dump shitcoin, that isn't going to fly with the lawmakers and regulators, they will simply not allow this to happen and brand it as an unregistered security.
Call me authoritarian all you want, but we have things called laws, regulations, taxes that crypto is great at evading.