I have never liked the idea of pension funds in fiat, the money would have lost so much of its value when it is available for spending after so many years. However, buying BTC is risky and i would not recommend that one should use their pension to buy BTC, especially when they don't fully know what they are doing.
In this case, it is an etf, i know not your keys; not your coins, but for people who would want to 'subscribe' to this, they may be happy if the responsibility of holding their coins is with a global financial firm.