Here's the missing question: Imagine you are a Eurozone pension fund or life insurer. You have to invest billions of euros very safely and eek out a return that is no less than inflation. How do you do that?
Inflation (HICP) was 1.73% in 2018. German Bunds, the safest euro denominated investment with sufficient volume, yield close to 0%. Now you look across the Atlantic and find that 10 year treasuries yield 2.63%.
The problem is that simply investing in treasuries wouldn't work because currency fluctuations would likely dominate any interest income. So you would need to hedge the currency.
The Bloomberg article is about why hedging the EUR/USD currency pair is currently too expensive for this idea to work.
It matters for European savers, including everyone who is paying into a defined contributions pension (e.g most workplace pensions). A significant chunk of those savings currently yields negative returns. The alternative is to take a lot more risk than you want to or are allowed to take.