Out of the hands of politicians and bankers and right into the hands of a script kiddie when the box that stores your wallet - be it locally or an exchange - gets hijacked and your wallet depleted. Or where nobody can get to it after you suffer catastrophic data-loss and you can't get to your wallet anymore.

If you want a hedge against a catastrophic collapse of the dollar (or whatever your local currency happens to be), there are innumerable other, better alternatives.

Besides, if there was such a collapse, who's to say that Bitcoin won't get dragged down with it? After all, more than likely you're using bitcoins to buy things that cost dollars.