It's simply an investment strategy; silver and gold prices have traditionally increased and so people acquire it for the potential gains. In my case, it's that and a means to hold cash without actually holding cash and the benefit of an increasing value, not decreasing.
A person should have seven streams of income, that's what will help a person attain financial independence and so I buy gold and silver as one of those "incomes" - Not that I sell any at this stage of course. Putting money in banks and hoping for viable dividends is misplaced hope in today's society.