The Joker theories on The Batman sequel are going viral
The joker is perhaps the most terrifying and legendary member of Batman's infamous rogues gallery, and Batman adaptations rarely wait too long to introduce their take on the Clown prince of Crime. The joker is introduced in the aftermath of Riddler's scheme to recognise his existence and tease his destiny in a successor to The Batman in the theatrical edit of The Batman, which gives him precisely the appropriate amount of screen time. If the movie had given him such a pivotal sequence in the middle of the film, it would have taken attention away from the Riddler's storyline.
Furthermore, while the sequence may feature Barry Keoghan's unsettling portrayal as the joker, replete with a New 52-inspired appearance, it contains no information that will not be disclosed later. The Riddler's origins as an orphan whose life was blighted by Gotham's corruption, as well as his misunderstanding of Batman, were better revealed in his own Arkham confrontation with Batman near the end of the film. The Joker's scene serves only to further prepare audiences for his destiny in Matt Reeves' Batman timeline, which his shorter scene in the theatrical version already does.