Just marketing gimmick.
My child has an Redmi 7 for a year and a month. Screen is protected with hydrogel foil and has a back cover. Even so, the phone was dropped from the washing machine, fel on the floor on its side first and then on the screen.... the screen cracked! Even of corning gorilla glass should protect the screen from shocks at under 1 meter high!!! Changing the screen assembly is half the phone price.  Stupid policy and expensive parts for a low cost brand!!!