1. Bitcoin will be global currency & fiat and bank no longer exist.
2. Better economy system because bitcoin can make corruption or manipulation almost impossible.
3. Bitcoin network's capability to process billion transaction without problem.
4. No monopoly mining by certain groups, company or government.
5. Blockchain technology can be used for something else than cryptocurrency.
If fiat and bank no longer exists then what's the point of bitcoins being volatile? Volatility is the feature many people loving it for making profits through trading bitcoins.
Bitcoin should be a form of crypto currency used globally but it's necessary to have fiat cash and banks who can pay interest to thse users.
I agree with the second point but I doubt it would happen as bitcoins is itself considered a form of helping money laundering and fraudulent transactions. It makes it easier to do so as it's anonymous and that's the major reason users make use of bitcoins.