Most of the time, anything associated with the world of superheroes and comics equates to a budget higher than $100 million. In the case of the new Joker film, the studio has managed to keep their budget at $55 million.
The budget suggests that the film will rely less on theatrics and CGI in favor of a more intense character study of the Joker. The goal is to keep the movie at a lower budget and make it for a more mature viewing audience. It is not the typical comic book movie.