Well it used to be the case that you could deposit money without giving any name address or any identifying information. In return they would give you a number, that is the only way you could access the account. Ideal for crooks to hide money. New international money laundering and other regs have pretty much put paid to that.
The thing about Switzerland is they are not part of the European Union so they have their own legal system which doesnt have many agreements with other countrys. When you open a swiss bank account they dont ask questions about it. Many arab oil rig bosses use swiss bank accounts etc for this convenient reason.