It would be silly for central banks to not be accumulating some Bitcoin just in case. They understand how money works..
There is always a cat and dog fight between the bitcoin regulation and the government as there are many countries who does not want to legalise bitcoin in their nation as bitcoin is usually involve in many illegal activities as like in selling drugs, explosives, money laundering and many more and no country wants to bring any kind of illegal activities in their nation and most importantly the terrorism and this is the main issue between bitcoin and governments and the solution lies in the problem itself as once it will get legalised all over the world then governments will keep eye over bitcoin activities.