The truth is if the government will be involved, the whole decentralised thing about bitcoin will be nonsense.
The government will surely take away the anonymity for it will be needing legal basis for transactions. The main third party that the bitcoin is against is the government itself because of high fees. So literally, if bitcoin is just like another currency, the only characteristic that it can be popular of is its volality, and it's access in the internet. When it comes to use, both fiat and bitcoin will have fees and not profitable anymore. ( worst case I can think of )
just the fact that the government is involved does not necessarily result in decentralization; the very nature and structure of bitcoin keeps it from being centralized without massive resources being dedicated towards control, for example, the 51% attack. unless a government specifically aims to control bitcoin and is willing to dedicate ample resources to this effort, this will never happen.
The government of some countries thinks that if virtual currency is given more priority then its policy on the payment currency will have an effect.The use of public on the main currency will be reduced.So they used to adopt any other currency as a legal offense.But, If they give permission to use bitcoin direct then all public use bitcoin.and increase bitcoin demand and continue grow.
In fact in present time most of the countries are still not aware from the importance of bitcoin. i think that with the passage of time as soon as bitcoin will become more populars its importance is also increasing from time to time, therefore i can say that such government will also understand the importance of bitcoin and will surely consider it as legal currency.
most major countries are starting to however. we can see major countries and nations that are leading in technology coming forth with their decisions on bitcoin in the recent weeks (china, korea, japan), and it can reasonably be expected that others will soon follow. i dont expect it to be long before we see which countries will come forth and we should be able to judge where bitcoin will develop and be adopted.