C
@orestiskon
You might have been confused by the advice given.
Persistent data means when you want to store information into an "object", via BaseContainer (or possible other means) THEN it is advised to use a plugin ID in order to provide for a unique storage identification. With "object" being a scene file, a polygon mesh, or primitive, a material, shader, tag, ...
Global variables, while potentially useful in certain cases, are not persistent. Same goes for local variables. This means, if you close and restart Cinema4D, the value will not be maintained. Unless you specifically store that value in a scene file, or separate file ... in other words: making it persistent.
I guess this whole discussion might better be located in the "General programming & plugin discussions".