One sure way for the government to control its people is to eliminate money as we know it. They then can turn off the supply (transactions) and no one can buy or sell.
I am not sure. All what I know about it is just an Internet's rumor. But in Mexico we shall have cash for longer, like typewriters and other things made out of paper. xD
I still use cash a lot, mostly because of metadata and the fact no one needs to know what yogurt I buy or how often I eat at certain restaurants. With a database on spending you could even begin to guess where people most likely are at any given time! Yikes!
Convenience there is, but I share the discomfort (and distrust). Try to pay cash still sometimes, to the mild derision of others and sometimes bewilderment of shops. (How would you like to pay? With money. Huh??)