From
http://news.yahoo.com/u-could-pressure-north-korea-tomorrow-quit-100-094000585.html via Time Magazine.
Superdollars, and the untold billions of (electronic) dollars spent combating them could be the wake-up call that finally forces us to think more clearly about the costs of physical money. If killing all cash strikes you as a little too radical, consider for a moment what it would mean to get rid of high-denomination banknotes. Who would be most inconvenienced if Washington were to outlaw $100 and $50 bills tomorrow? Cartel bosses in Juarez, Mexico jump to mind. So do human traffickers in China and Africa, aspiring terrorists in Afghanistan, wildlife poachers, arms dealers, tax evaders, and everyday crooks who hold up mom and pop groceries. And, or course, North Korean government officials.
Also mentioned on /. with surprising little of the usual vitrol when bitcoins are mentioned.
http://yro.slashdot.org/story/12/02/24/1949204/north-koreas-high-tech-counterfeit-100-billsFor every small increment of shady financial dealings that bitcoin might make a wee bit more convenient, there is vastly more volume and more dangerous stuff already going on with hard currency.