This is a good question in this economic climate. As you probably know that the price of gold and silver has gone up considerably in the last few years. Let me offer the disadvantages first.
There are a few disadvantages for digging for gold. In order to to this successfully, you will need a mining company. Mining companies are not easy to setup due to the great costs that are associated with it. In addition, there is no guarantee that you will hit it big with gold even if you started a mining company. Finally, the price of gold can fluctuate greatly. So, even if you find gold, it may not be all that profitable.
With that said, there are several advantages. First, many economists believe that the price of gold will hold and even go up. From a historical perspective, gold has gone up and retained its value. Second, one of the things that many central banks are doing is printing money. When this happens, the value of money goes down and the price of commodities goes up, like gold. Therefore, gold can be the ultimate hedge against inflation. Finally, in the event that a currency goes bust, what you want is hard assets. Again gold can be very valuable at this point.
One of the very best to read on this topic is Jim Rogers. I will add a link to his book.