Argentina went through something somewhat similar a while back. The idea behind PM's is that you exchange them in small amounts frequently for what available currency you needed that day and then went about buying what is needed at a point in time. The PM's maintain a relatively constant purchasing value and you exchange them for 1000, 10000 or 100000 dollars of local fiat (depending upon their value that day) and get the same things you normally would for the same relative price you would normally pay. As the old standby goes... an ounce of gold in ~1873 would buy you a fine banker's suit or a Colt Peacemaker. Today, an ounce of gold will still buy you pretty much the same things. Of course, back then we said those things and the ounce of gold were worth ~$18, and now we say they are worth ~$1600. Same thing, just a different perception of the value of the fiat measured against an item. Given enough time, most fiat currencies have eventually failed, been replaced or revalued. This sort of stuff isn't just a "third world" sport.
For more info, Google for Ferfal's info on surviving hyperinflation in Argentina. Soros had some fun shorting the English Pound a while back as well.
