As of now gold and other presious stones only competition for gold. In few years bitcoin would be the best stock around the world. Still i do not know why any government not accepting bitcoin is the centralized money.
Bitcoin is not centralized, it is decentralized which is the only common reason why governments are not accepting it, because they will not be able to track the transactions and money being circulated in the way of bitcoins, and so there is no possibility left for them to trace black-marketers, drug sellers, dark market dealers and terrorist activities which include money laundering.
Oh, they do accept it, at some point the USA government was one of the biggest bitcoin holders in the world.
You'll be amazed on how traceable bitcoin is, and it will become even more as it is adopted by more and more people.