I remember there was an article on HN not so long back about why poor people dont trust banks. Well, without bank accounts how do you process billions of dollars of micro-cash payments ?

Actually, this is the biggest reason for the build out of the Aadhaar project or the Indian biometric ID project. It is less for reasons of trying to track the common citizen (although I dont doubt for a moment, it will come to be used like that), but to ensure credible, direct debit of cash to the poor.