Buying all 50 nifty shares and managing is much more cumbersome than buying index funds, also to match nifty weightage individually it would cost more than 10 lakhs, etf or mutual fund is the right way to do index investing by retailers. Also I personally would recommend to buy index mutual fund to invest in nifty stocks than etf for new investors or users who are not much versed with market dynamics. Also check this thread on etfs.