I would definitely choose the Bitcoin pension system. The main reason for this is of course the high return. The pension system is basically deposited in the DCA strategy for about 30 years. Now think, if you save your money regularly in Bitcoin for 30 years, how much return can you get?
Fiat loses value day by day due to inflation, even if you make a profit on your fund, it will not be equivalent to Bitcoin. Suppose if you deposit $100 per month in your pension fund, then your pension fund will be deposited in the year $1200 and in 30 years it will be $3600. Now if we expect 4x profit in 30 years, then the amount will be $144k, which is much more than 1 Bitcoin at the present time. This was my simple calculation, but from my point of view, the Bitcoin pension system will pay several times more than the Fiat pension system. I would definitely choose Bitcoin.
Bitcoin pension systems are much more meaningful and effective than fiat pensions because naturally everyone is now witnessing that the market has reached new highs twice this October. So if the pension money is kept in Bitcoin, then it may be possible to make several times the profit from it. But if it is kept in fiat currency, its value will not increase, but the value of that saved money will decrease due to the increase in the inflation rate. Moreover, an individual may be able to analyze which system to invest their pension money in based on their risk tolerance, so I'm mentioning the benefits of holding Bitcoin and fiat currency.
It is largely correct that Bitcoin has a limited supply and is free from central bank and government control due to its decentralized process, and most importantly, it offers the potential for high returns, On the other hand, fiat will only reduce its purchasing power and it is controlled by the government and central bank. By the way, maybe the calculation of your total amount of money over 30 years is wrong here because if someone deposits $1,200 into their pension every year, it will be $36,000 in 30 years.