The global financial system that we have currently is a very complex network of banks and other financial institutions. The global market is dominated by a handful of massive international banking institutions and local and independent banks are decreasing rapidly.
Banks provide a highly important service. Whether you want open a basic savings account, or to send money abroad, banks are capable of providing many services. Since financial institutions all over the world are linked to each other, understanding how exactly the global financial system works can be difficult.
There is always a danger to letting to decrease competition in the market, let a handful of providers rule the market and to let institutions become too big to fail. The same goes for banks. Today there are very few banking corporations that dominate the global financial market.
The recent bail out of several private banking giants by different countries around the world shows that banks are even more powerful than we may think. Banks essentially control most of the financial resources around the world. In this light, it is important to encourage small independent banks in local communities.
Even to someone who knows nothing about economic theory, it is clear that letting a few global corporate giants with provide interests to rule the financial systems of the world is a bad idea.