There is nothing wrong if a country's central bank believes the right thing to do at the moment is to hoard bitcoin as much as possible depending on their economic need and their intended target. The effect on the market could be good or bad depending on the side one founds himself and the interpretation one is giving to it.

Assuming that the amount they acquire is huge enough to make impact on the market, then looking at the good side, it means there would be scarcity which would then increase the price of bitcoin in the open market. It also sends a message to the general market that if a whole government could be acquiring, then it shows a further testament that this is the real deal.

On the other hand, if looked at with some level of skepticism, it could mean that what they are trying to do is to disrupt the market by acquiring much now and then dumping thereby collapsing the entire market which would take like forever to recover. Going further on that could even mean that acquiring much means acquiring control that bitcoin philosophy negates from the start.