What is craft books useful for? I mean what kind of books? what is the benefit beside maybe a day job check?
You could also use it to repair damaged books. Or know what to do to save (the info in) a book that got dropped in the water.
Enchanting spellbooks
making tomes to scribe you notes in, keep maps stuff like this
making enchanted books
That actually sounds like a good 1 rank in craft for wizards.
That is exactly what I had in mind when posted the question!