I think OP misses the point. Bitcoin was created so that money would be decentralized.
People would be in full control of their funds and not rely on banks or other financial institutions for storing, sending or receiving regardless of the amount.
Satoshi famously included this comment on the very first bitcoin transaction
The Times 03/Jan/2009 Chancellor on brink of second bailout for banks.
Banks operate on a basis of
fractional-reserve banking, which allows for reckless lending that lead to fun events such as the subprime mortgage crisis.
They create money from thin air, lend out at high interest rates while paying a much lower interest rate for deposits.
As seen in Cyprus and Greece recently, when financial institutions get into trouble people panic and do "bank runs". Since there is not enough money due to the fractional-reserve system, banks resort to limiting or freezing your money. Governments and even services like Paypal can freeze your funds at will.
Yep, your money is not truly yours.
Meanwhile the government might start desperately printing more money and your savings will be wiped out by inflation. Classical examples are Argentina and Zimbabwe
With bitcoins, fractional-reserve banking and mass money printing simply wouldn't be possible.
And with the advance of hardware wallets, online vaults, multisig and so on, keeping bitcoins safe is getting easier so banks would only be useful for keeping fiat currency.
Essentially, if bitcoins really reach mass adoption, banks would drastically loose their importance and would be forced to change their modus operandi.
Oh yeah, no more billions of tax-payer money for bank bailouts either