Purpose of the bank is to store all your personal money and to show you other information partaking to your assets.
Clickingor will take you to access your Bank page.

Assets shown include:

• Money you have on hand

• Money you have in the bank
• Interest earned
• Resources you have stored
• CPUs you have earned
• Experience earned and how much until next level
  
• See the Global Bank total
  

Money deposited into the bank cannot be stolen by any type of attacks. But your resources, CPUs, and money on hand are always open to attack unless you are hidden.

See also:
Global Bank
Money