I need help responding to this question. 3. The Wall Street Journal reports that yields on two-year government bonds issued by eight European nations...

I need help responding to this question.

3. The Wall Street Journal reports that yields on two-year government bonds issued by eight European nations and Japan were negative on Wednesday, indicating buyers' willingness to pay governments to hold their money. Why would anyone ever buy a bond that is guaranteed to lose money?

My anwser was 

They do this by stimulating the economy for Central banks.  They also think that if the interest rates continue to dive they will make more money, and they think in other countries like Greece that the euro will rise. 

But then I was asked this and need help replying.

In reflecting on question 3, do you feel that stimulating the Central Banks is an effective means to influence the interest rate and ultimately the financial sector as a whole?  I am interested to hear your thoughts on this.