Before the '90s, horror movies of all types relied heavily on practical effects to bring terrifying and gruesome creations to life. One of the best examples could be seen in George A. Romero's zombie movies like Day of the Dead, which opted for extreme realism as zombies ripped their victims to shreds. However, as technology advanced in the '90s, there was a new way to enhance the movie-going experience through computers with computer-generated imaging. This was best shown in Steven Spielberg's Jurassic Park, where creations like the T-Rex were both practical and computer generated to make the dinosaur more believable.
Source:https://www.cbr.com/how-the-mummy-brendan-fraser-elevated-cgi/