Bitcoin being an E-curreny can't make bank dissappear; for one thing, here in our country Botswana, we get alot of power cuts, relying on online currency is a really bad thing. Its best to know that you have something physical to use even if the whole world goes internet dark.
That's the risk of digital money if the world will experience some unexpected scenarios such as mass power interruption.
Then it cannot be a good substitute for banking system for they still have the best system when this kind of scenario happens.
Unlike with bitcoin, it needs power,internet and computer.