I like that idea. haha However i think all land over earth is owned by a government/person, so it's not that easy.
I think the key just gets the blessing and permission from the government. After that happens then bitcoin will grow very fast, many stores and agencies will adopt bitcoin, but to get legalization from the government is not easy, may have to remove the decentralization of bitcoin?
If bitcoin has been legalize, the government will take in full control over tax in bitcoin. The government knows that they are losing taxes in terms of digital currency. Bitcoin will grow fast if it has been legalize but how about the users and earners of bitcoin? Does this thing has a positive result?