The history of the blacksmith and the caligraphy index were rather boring, filled out countless technical details and why they were what they were.
Aside from that of course there was a lot of valuable information inside of both, for example Guilliman was introduced into inscriptions in like the fourth page of the history of the black smith.
Inscriptions were a form of empowerment humans had come up with hundreds of years ago, or according to the old man was rediscovered.
It allowed for human slayers blessed with particular Affinities to impude man made weapons with the output of that ability using symbols.
In essence it was humanities solution to the scarcity of beast echoes.
