bitcoin has no central government so any of gov department cant track the transaction so some of the contry still bann for the bitcoin use 
Bitcoin does not have a central government but everything is transparent when it comes to bitcoin as you can check each and every transaction in the blockchain. So it is basically not a untraceable currency like you think it is.Why government are not approving is a different debate altogether as they might be learning about it.Bitcoin may not be 100% anonymous, but it is quite difficult to trace the transactions back to a particular individual. I am not saying that it is not possible (for example a few users traced back the Sheep Marketplace thief), but it takes a lot of effort and time.