Relax Luther, it's much worse than you think.

Sydney posted some good questions on What is Arbitrage?.  I'll take them one at a time over the next few weeks.  First, I have to contest the assumption that money in the bank is totally safe and secure.

It is true that money you have deposited to your FDIC insured bank is guaranteed by the federal government against loss.  If your bank goes bankrupt, and they don't have enough cash to pay you back, the FDIC steps in and pays you for every dollar up to $250,000.  Banks and the tax payer fill the pool to provide this insurance.

But what about the robot apocalypse?  Your trust in the bank and the FDIC rests on the belief that the federal government will always be there.  I think this is a fairly reasonable assumption, but you should be aware of it.  Also, one could argue that your American dollars won't be very useful in this scenario anyway.  Food, water, and a gun big enough to hurt robots would be preferable.

Here is the other, and more applicable, problem.  Your money is losing value in the bank.  Very few banks pay interest that is higher than inflation.  So you might get paid 1% a year by your bank, but when inflation goes up by 2%, you lose.  You have a little more money, but it doesn't buy you as much stuff.

I understand the desire to accept zero risk (assuming no robot apocalypse).  There are other investment options available to a risk averse investor that pay better than saving accounts, such as United States Treasury bills and bonds.  I'll describe them in detail soon.