Matt Levine about this on today's Money Stuff:

"I know this is bad but I find something aesthetically beautiful about it. If you have a pot of money [pensions] that is immune to bank runs, over time, modern finance will find a way to make it vulnerable to bank runs. That is an emergent property of modern finance. No one sits down and says “let’s make pension funds vulnerable to bank runs!” Finance, as an abstract entity, just sort of does that on its own."