Historically, the "at cost" PoD option (see Reward Descriptions) has been used by Onyx Path as a means of granting a physical book to backers during the (often) lengthy process of printing the deluxe hardcover books. Due to the complex manufacturing requirements, printing and assembling the deluxe editions can take additional time. so Print-On-Demand options have been exercised in the past to mitigate some of the waiting.
Currently, only select Reward Tiers will receive the "at cost" PoD option as a reward (see the Complete Reward Tier chart on the main page). This Kickstarter campaign is built and driven to publish and distribute a prestige version of this book, and having backers select that reward (the hardcover) is the a key step in this process.
Many, if not all, of the other books offered as rewards will be available in PDF and PoD form at some point in the future. If your primary consideration is to receive a PoD version of any of these books, it may be in your best interest to wait until those product options are available.
If your goal is to help facilitate the production of the prestige hardcover book and distribution of Geist: The Sin-Eaters 2nd Edition, backing this project has the additional benefit of building other related supplements and rewards, as well as offering many items combined into a single Reward Tier.
PoD options for one/many/all of these supplemental titles may appear as an Add On reward unlocked by a future Stretch Goal, but these options are not the primary focus of this campaign.