It is accessible, it is easy to perceive, it gives free rein to the imagination of the viewer. And it has accompanied a person since childhood. How many 30-year-olds today don't tremble at the sight of old Disney or Soviet cartoons? People love 2D animation, believe in it, and are willing to pay its creators.
The basic principles of creating 2d animated video have not changed much since the early 19th century. Artists draw a set of "flat" pictures in two dimensions: width and height. Each next picture is slightly different from the previous one. Due to the rapid change of pictures in the frame, the viewer feels that the image comes to life. This is enough to make the movement of objects and characters seem quite smooth and realistic.