Cash might go worthless. Probably the best barter items that work as currency in an economic times are ... cigarettes, coffee, and alcohol.
If we're talking in the next 1-3 years, yes, eventually cash will be worthless, but this won't happen overnight. You'll still need cash to buy stuff until the system dies. But this will be a "controlled" implosion of the system, so it will happen gradually at first.
I predict an increase in "cyber attacks" on banks, payment systems, etc. This might shut down banks, ATMs, credit card readers for a few days. (This is why you need to have cash on hand). Then the govt will pass some huge, sweeping bill aimed at "keeping our financial system safe". This bill will effectively put the govt in control of the internet, and all e-commerce. It will also give them control/surveillance over alt political sites and alt social media sites.
When the govt runs the internet, then the US digital currency can be unveiled. In between all of this, there will be financial chaos, so that the people will accept this "solution".