Obviously there were other choices. But large investment fund managers now mostly operate on the FOMO principle. They don't want to look stupid by missing out on the next big thing. But if they take a loss then they can explain it away because "everyone else was doing it".

At a more fundamental level, this is just another example of the principal-agent problem. Pension fund managers optimize for their own careers rather than for the financial health of retirees. This is one of the reasons why all defined benefit pension plans should be eliminated and replaced by defined contribution plans.

Bonds aren’t risk free. Just asking holders of Argentina’s.

sigh Whether the bonds have a positive yield and how currency is issued have no relation. There have been plenty of positive yield bonds during the gold standard. Indeed, "hard money" standards tend to make borrowing at high interest rates more necessary.

This is like the bizarre argument sometimes made that hard money will end war; that's not how it works. The war will happen anyway and a means will be found to pay for it. Gold was heavily used as an inter-governmental currency in WW2 - resulting in a few very expensive shipwrecks.