Bitcoin can be used as a national currency, no reason why it couldn't. Governments can collect their revenue from taxation and then spend the funds accordingly.
Bitcoin will never be used as the USA National currency as someone will want/need to control ...either Banks or Govt. but would probably co exist with a new National crypto currency.
The USA ( and a few others) Govt did not used to be the Borg Queen a long time ago..but now it is. Govt is motivated by individual ( personal ..get rich or re-elected) goals in the 1st instance and good work in the second intance ( based on the If I'm not elected ( which needs financing and money in MY bank) I cant do any good..doctrine)
While the Fed is outwardly private owned..the influence Govt has is in fact strong, if not effectively absolute..they will threaten to change the system and kick the bankers out if ever a major request to them is denied...Congress actually has power to do that if ever they want to...It is just convenient for Govt. to have a scape goat to blame if things go seriously wrong
a balanced view is here ( without the stated recognition that Govt has them over a barrel IF ever they want to remove their power)
http://www.monetary.org/is-the-federal-reserve-system-a-governmental-or-a-privately-controlled-organization/2008/02
Another disturbing thing about the British news report is its reflection of the naive belief that more regulation means a safer, less risky financial system and economy. Big Government here and in Europe has perpetrated the astonishing myth that the recent financial crisis was caused by reckless and greedy private-sector bankers. No wonder the public howls for bankers’ heads. The real villains here were governments, particularly central banks.
http://www.forbes.com/sites/steveforbes/2013/07/24/big-government-and-central-banks-the-real-criminals/
I agree with this viewpoint.
Also, Bitcoin itself can't help any national economy to get rid of debts.
Economy (and specially World finance industry) is still based on USD, and most countries asking for loan in USA, and this will not change soon.
If bitcoin will be regulated and have its own bank this story may be different but because this will never happen we can't think that Bitcoin can directly help any of this 11 countries close to bankruptcy...