I would add Books as simply collectible items - I think actually having the in-game Books of Sorrow that I could flip through in my item menu would be totally awesome. On that note - I would also love it if artifacts had some level of interactivity while examining them. We can rotate ghosts to examine them, it would be neat if artifacts could be examined in the same way - perhaps you could find a secret compartment that you can infuse with spirit bloom, or an inscription that leads you to a certain place on the patrol maps at a certain time of day, or re-configuring parts alter the properties of the artifact - or optimizes it. It would go a long way toward adding some mystery, lore, and increasing the value of these particular items.