I heard the news, that banks are afraid of bitcoin and can replace banks, because the excess of bitcoin is much compared to local banks
The major fact is that
Centralised currencies have nothing to do with the decentralised currencies. There are several threads similar to this and this question has been already answered several times. Bitcoins will never take over the fiat currencies because they are been nationalised and also it is impossible because of the national governments. Government can never make this happen because the centrakised currencies gives them the ease to track and manage the supply of which compared to the decentralised currencies is not possible.