Question on index funds

Im 16 and learning about the stock market so i dont have a good understanding for economy, businesses and stock of any kind. As many of the sources ive read most suggested index funds as of an investment for average people. Correct me if im wrong but i see little to no benefit of index funds. First lets compare ivesting in index funds compare to investing in big, credible companies with a buy and hold strategy ie apple, tesla, amazon all of them has a high growth rate beat index funds by a large margin with low amount of risk since these company most likely wont go down by any means. Second the reason most go for index funds for its low risk but as far as i know bank saving account hold a 6.6 to even 8% with no taxes and less risk than index funds so whats the point of it ( i live in vietnam and this is a reference to vietnamese banks ) . I appreciate all the feedback and as my english is mediocre since im not a native woth little knowledge i would appreciate if you notes explain any technical terms but if not its ok ill google it .