Check out this informative video from Vox, and it examines the digital doubles that are used to replace actors in superhero movies. It breaks down and defines the use of these digital doubles and demonstrates that they are used a lot more than you think in places that you wouldn’t even think they would use a digital double.
On June 9, 1995, Batman Forever introduced audiences to what was likely the first CGI stunt double.
In a few brief shots, a digital double lept from tall buildings and swung on a grappling hook, and was used to convince viewers that Bruce Wayne was more “super” than the average man. Since then, superheroes and digidoubles have gone hand in hand. Protagonists in superhero films often wear masks or skin-tight bodysuits, which makes them perfect candidates for digital replacement; fabric is way easier to replicate digitally than skin.
Technology has only improved over the years, which means digidoubles are used for so much more than just “super” sequences. Today, digidoubles are used to give filmmakers and artists flexibility. Instead of being locked into what they’re able to shoot during principal photography, they can add and remove shots, completely change characters’ costumes, and rewrite the script if they need to — long after filming is over.