I would like to understand some intuitions behind the following causal graph/SCM.
Where as $X_1, X_2$ are expenditure on promotional activities. My main interest lies in understanding the fact that even though people HAVE to visit the store to buy something(generate a store sales) $X_1, X_2$ can also have an effect directly on $store \ sales$ beyond their effect on $store \ visits$.
E.g $X_1$ may generate a large amount of store visits but the customers arriving to the store are not eager to buy anything, on the other hand $X_2$ might bring few customers to the store but the ones that arrive buy a lot of items.
Thus i am trying to justify intuitively/examplify why we need the direct effect from $X_1$ to $store sales$ when we keep the direct effect $X_1$ to $store visits$. Bare in mind that customers have to visit the store in order to purchase.
I.e my intuition is that they may affect store visits differently from how they affect store sales, would this be a valid interpretation?