The German economy is considered the largest economy in Europe and the 4th largest economy in the world with a total GDP of 4,000 billion USD, only behind the US, China and Japan (2022 data). So it would be naive to think that the German economy needs the help of those bitcoins. We cannot know exactly why they are selling bitcoin at this time, but it is certainly not because they want to save their economy with that small amount of money 
.
The return of Mt.gox or the government selling bitcoin are all good news if we ignore the short-term impact. Even for those who understand how bitcoin works, this is another great opportunity for them to buy bitcoin at a discount rather than panic selling.
.The return of Mt.gox or the government selling bitcoin are all good news if we ignore the short-term impact. Even for those who understand how bitcoin works, this is another great opportunity for them to buy bitcoin at a discount rather than panic selling.
Germany being the largest economy in Europe doesn't mean that they don't need the money from the sale of Bitcoin. The money might be insignificant when compared to the total GDP but selling the coins now shows that they need money. Maybe they want to use the money to finance a project or pay some financial obligations. It is also possible that they are selling to make a profit. They might have plans to buy in the future when the price drops.
I don't know the reason or purpose they sold those bitcoins but some people said they sold bitcoins because they needed to comply with the country's laws because it was confiscated money from criminals. But I believe that they will not sell those bitcoins because their economy is weak and they need that $3 billion for economic recovery. Just as they do not intend to speculate like us because if they intend to speculate to make a larger profit, they will sell in silence instead of making noise that causes the price to suddenly decrease and they will sell at a low price.
If they really needed that money and intended to manipulate the market for speculation, why didn't they sell when it was priced at $72k but sold when it was priced at $60k or even $53k?