Bitcoin can become successful on annual basis but they cannot completely erase the use of banking system because still people are in favor of using bank. Most of the people are not familiar with bitcoin so I think acceptance of bitcoin for them will be difficult at start as old people rarely trust digital money and digital investment.

Bitcoin was considered as a currency in past but now you will know that instead of using it as a currency people are using it as an investment  tool and I think in future it will just be use to increase the value of cash.