Auto Drawing Tool uses a combination of the build modifier and the Freestyle renderer to simulate drawing animations.
This is a new Blender add-on. The add-on makes drawing animation by Freestyle with build modifier.
The add-on is useful to make fake drawing videos, for example, presentation of a product or education videos.
Also, if you are an elementary school student, you can make a drawing video for homework of art during summer vacation. Teachers would praise you for your skill.