The banking system has a legacy of offering various financial services to its customers. They offer convenient ways to spend money, such as cheques and credit cards, but the storage of money is their base service.

For many centuries, banks have been a safe place to keep money. Customers rely on the interest paid on their deposits, as well as on the government insurance against theft and insolvency. Savings accounts have helped make preserving the wealth easy, and accessible to a large population in the western world.

Yet, some people still save a portion of their wealth as cash or precious metals, usually in a personal safe at home or in a safety deposit box. They may be those who have, over the years, experienced or witnessed the downsides of banking: government confiscation, out of control inflation, or runs on the bank.

Furthermore, a large population of the world does not have access to the western banking system. For those who live in remote areas or for those without...