It was an easy method to provide the background, especially for the Aeon throne.
For rule books especially, I read the chapters on tablets so I don't have to load the entire gargantuan PDF into a small tablet. Losing that ability lessens the utility of the PDF provided by a subscription.
The take away from that is, if I don't use the PDFs, the subscription becomes less useful. If the subscription becomes less useful I am much less likely to purchase some of the products.
Simply put, if rulebooks don't come with by chapter PDFs, I may very well cancel my subscriptions.