There are other more practical examples too. For a time, the banks in the United States would issue their own paper currency that could be redeemed at the bank.

There are other more practical examples too. For a time, the banks in the United States would issue their own paper currency that could be redeemed at the bank. The paper money traded up or down based upon the reputation of the bank and, to some extent, the distance to the nearest branch. It's pretty much an exact analogy to the world of alt coins, except the physical details like the location of the bank made a difference.