First of all, the simplicity of the action subject has a great influence on the workload of production. Simplifying the actors can double the work efficiency.
One of the most obvious examples is the small "stick figure" kung fu series. As can be seen from the figure, the main body of animation is quite simplified, and the workload of making an action film with such a main body is affordable even if it is made frame by frame.
Imagine making such an animation with the image of a real person as the subject of action, and the workload will increase a lot. The methods that can be applied are: subject simplification method, circulation method, selective gradual change method, substitution method, replication method, reprocessing method, masking method and so on.