I can see where from the New modelers point of view, if some models are designed with tabs and some models are not, why don't the models without tabs have the strips already included.
lately I have been including the strips in my designs, to include the color that would show under any gap. especially if the strip is a curve or complex shape.
In a larger model it is surprising how much room strips take up on the page. So to save costs I'll leave them off to lower the amount of ink used and number of pages required for the model. especially if the tabs are simple straight strips.
So for new modelers, making strips or adding tabs, is a skill that is almost immediately required to learn, as is scoring your folds...