The returns you get for investing in cash may be very low indeed, but there is nothing quite like cash when it comes to security and liquidity.
You need cash for your everyday living expenses, but you will also probably have times when you need to hold some of your investment assets in cash, whether for short periods or for several months. This could be while you are taking a pause to rebalance your portfolio, if you think the market does not offer good value, or if you suspect a fall in markets is looming. You might also want to opt for cash if you have a sum of money you want to put to a particular use and don’t want to risk losing any of it. Or you could be approaching or at retirement and simply not want to expose yourself ...