bitcoin for the future may be used as a legitimate means of payment such as credit cards and others 
But it may or may not, and if it happens, then it take very long time to happen. Because most of the governments want to track the transactions and source of income to tax but in bitcoins, it will be difficult so world governments will not allow using bitcoins so easily.
Nope not like that buddy. Actually the hidden reason is government sector people will not able loot or scam anyone through bitcoins.
This is actual reason why government is not accepting as centralised money.