Bookstall I see numerous phones being used, but very few books now. Only the traditionalists (like me, I admit) get out their Red Diagrams, or similar.
What is appreciated at 2 towers where I ring is the tower copy of the blue lines in A4 spiral bound format. With that, several of the band can look over one copy together to sort out or explain a detailed point in the method. At that size, it is far easier for several people to see the page and where the a particular point of concern arises, rather than looking at separate books or phones. That however, is not a CCCBR publication, as far as I recall.
The other merit of online material, is that it can be kept up to date readily. This may not be of concern, say for basic blue lines, but for some items, that is important.