This is generally the same reason there are buyers of sovereign debt (i.e. Treasury Notes) at a negative interest rate.
If the Eurozone collapses, as is more possible every day now, then that's a case in point for diversifying away from Euros. Some other choices in this Great Recession are USD, U.S. Treasury Notes, Japanese Yen, Swiss Francs, etc, none particularly attractive right now. The Chinese Yuan isn't a viable choice because it is pegged to the dollar.
[Edit:] The point is to deal with the current high risk of currency free-fall, not your normal everyday investment ebb and flow.
Because people are heavily influenced by the "panic! panic!" media nowadays.
Supposedly things would "never be the same again" after September 11 and the industry for comedy would collapse. Then we were meant to be dying of avian flu.. and then swine flu. And then the economy was meant to collapse some time in 2009. And then.. oh yeah.
Another panic, another year..