People are already trading bitcoins for other property as a means of exchange just like money. Why would you need other money when Bitcoin is worldwide?
It is necessary to use the opportunity to pay using bitcoins without paying taxes while there is an opportunity. I think the state does not want to have such a currency.
And, the state in America does not want you to know how easy it is to stop paying taxes, legally. Listen to Karl Lentz https://www.youtube.com/user/765736.