The government and the banks won't allow the system of digital currencies to rule the world. Even if digital assets are more efficient, low cost and more secure, they won't allow it to happen simply because they have no control over it. And in the future for sure, cryptocurrencies like bitcoin will be the most effective form of doing financial transactions.
Banks really disagree with the existence of bitcoin. they consider this to be their competitor because of the blockchain that makes every transparent transaction able to create a new system that is more trusted.