What are actor types and why should I care?
When an entity is created, its components must be added to the relevant systems.
The concept of actor types is a way to make it simple to create and manage entities.
An actor type will take care of adding an entity's components to the relevant systems on creation.
Instead of directly adding the components to the relevant systems when creating an entity.
In this case you have to manually make sure that the entities components is added to each relevant system.
An actor type takes care of the creation of an entity, hiding the details.
This means that the creation of an entity will be trivial.