Hi guys.

Is it just me, or does this notebook suggest some hidden quest/treasure? But I can't seem to figure out what to do to with it. Anyone had any luck?
By the way, I have com​pleted the "Regrets Worth Trading" quest already, so perhaps it had something to do with that?

It's related to it, but I don't think it's part of the quest.

Well, there was a new dialog option related to it, when I returned to the chapel in town. The priest there wanted the journal, but I chose to keep it - but no further clues to what use it is.

The priests are probably selling those trinkets to the giftbearers and that journal may be evidence against them. Honestly I haven't tried that, but if it ain't some kind of... "oh, those giftbearers are forcing us to do this, please rid us of them" scenario resulting in a different outcome then it's probably just some minor detail.