The truth is, if everyone use bitcoin to save for retirement, then bitcoin will rise to at least millions per coin, thus make that pension plan a huge success, it is just a matter of time before major institutions start to dive in. Currently lots of private person already started to do private long term savings using bitcoin

For 5 years performance, bitcoin beats every single investment in human history when it comes to risk adjusted return: With a 1% risk you get 100% return. And typically for a successful investment, with 1% risk you get 3% return. So from the view of a pension fund (they typically measure 10+ years performance of any investment), this is the top choice, just need regulation to be in place