Like my edge lord title?
Keeping money in the bank is the equivalent of letting the corrupt elites steal from you in the form of inflation - but just enough theft to keep the masses complacent. I am going to use a physical good as an example (Gold)
Inflation rates for 2009-2018 have averaged around 2.8% per year, calculated out for that same time period the cumulative inflation was 17.7%, meaning if you earned the same amount of money each year, your wages in 2009 would pay for 17.7% less stuff (food, goods, etc) than it did in 2018. In different terms if you hold onto your 100$ for 2009-2018 you have really lost money due to inflation - the value of your money has decreased from various made up bullshit they use to steal from us by not backing our currency in gold and instead backing it in fairy dust and "fuck you's"
Another way of thinking of it - - for an average yearly inflation rate of 1.79% (a number cited for 2009-2018 yearly inflation on a different website) your 100$ that you made in 2009 is worth 85$ today.
Around this same time - despite a significant spike in value from 2010-2013- the 2009-2018 price of gold increased from 30,000$/Kg to 40,000$/Kg, or 4/3 (133%). If you subtract inflation from this (the earlier quoted ~17.7% over this time period) your 100$ that you bought in gold has netted you a profit of $15.3.
Now, the value paper money is rotting, and the value of gold is increasing, why would anyone risk averse want to hold any significant amount of money in a bank? (aside from a small emergency fund until you can liquidate assets, and small checking account for monthly expenses?)
If you have means you can save your money by "investing" (not have money systematically stolen from you) in safe bets like gold holding companies, or put retirement funds into a gold IRA, or buy straight gold bullion and stick it in a safe deposit box/ hide it in a safe somewhere in your property (probably only good for smaller amounts)
If you don't have means (think <$50k/yr), you are more likely to live in higher crime areas, which makes it less safe for you to buy gold bullion - which you already pay a premium for - especially in lower quantities. Possible solutions - Safe deposit box in the (bank).
Meanwhile our system incentivizes us to allow others to gamble with our retirement savings on the stock market (401k), which generally has provided good returns in the past 120 years, however, with notable exceptions. If you were to retire during 2008-2010 you would have not been happy. The continued investment into these programs assumes the next 50 years will be the same as the last 120, which saw the most economic development, invention, and for the past ~75 years saw the greatest peace and prosperity in human history. With relatively wide open physical space for human development with relatively low competition for resources compared to today, it is reasonable for one to be risk averse.
Would a risk averse person trust their life savings to a non-accountable body that decides to devalue their currency every year, or a currency that billionaires are excising value through government manipulation, or a currency that certain billionaires are trying to short by destabilizing entire countries through political terrorism?