The idea that bearer instruments would no longer be available is cause for serious concern. If things do go wrong with our communications infrastructure, the absence of cash could cause chaos to set in sooner.
It'd also mean that every transaction could be monitored, and potentially blocked, neither of which are good things. That's without mentioning potential for taxation. Add the fun of clerical errors into the mix and things could get really hairy if things go wrong.
Bitcoin won't gain acceptance as it's not backed by a national government. At least not in the short to medium term.
Barter evolved into cash; take cash away and barter will resurface. Eventually someone will try to impose some sort of order on the bartering, and hey presto! Cash again. As Mark has said.
-- "Happiness only real when shared" C. J. McCandless