Since you can include hundreds of stocks and other investments in index funds, you are more likely to invest with less risk.
This simple diversification that index funds allow will make it close to impossible for you to suffer any big losses in case a company faces any bad situations.
Index funds are one of the last expensive investment options unlike other actively managed funds. With index funds, you do not need a team of research analysts for research or a fund manager to select the stocks. An index fund manager only buys the stocks and they do not need to put their expertise in their portfolio.
On the other hand, index funds have a few cons as well:
Vulnerable to market swings and crashes
Lack of flexibility
No human element
With index funds, you do not get to pick and choose what stocks you want to buy and those that you do not want to buy. For any investor, this is not good because you will end up having stocks you do not want or even miss out on other stocks because of the index you have chosen.
The thing about investing in index funds is that you will not get any big financial gains in the early stages of the investment journey.
You have to be fully invested in the index funds and pick the right indexes if at all you want to start getting any returns.
If you are persistent and consistent, you will start making the big financial gains in the long run.