Blurbs explain uses where not obvious.
Maps, atmospheric splash images, & when you actually build a settlement you think a lot more about what's in it and how it got there. Pairs well with Ex Novo.
I've been setting the game world's current day a few rulers into the 'Fall' era.
Develop the original fate of an undead BBEG, clashes between ancient civilisations, or current-day opposing forces if you stop just before the showdown.
Especially for sentient weapon personalities and generating unique abilities off an item's history.
