Books can be useful to gain access to certain experiences, like having some passwords on some files you'd rather not spend all your time learning to crack. Too bad the books are mostly encrypted too, so either way you're going to spend time if you want to go into deeper waters.
With the proviso that so-called scripture varies quite a lot in many respects, I want to point out that most of that which is emphasized by the doctrines attached to them basically
jhas to be cryptic or even all-out contradictory in order to remain influential.
Clear scripture would be easily understood and therefore easily rejected by those who disagree with what it says. By contrast, unclear scripture receives a lot of benefit of the doubt from people who are already willing to presume the best and avoid arguments with family and friends.
The end result, counter-intuitive as it may be to the faithful, is that demographic success comes more easily to unclear scripture.
That said, it must be also pointed out that scripture is among the poorest of all existing means of religious transmission, to the point that I would argue that it consistently fails and can only be truly useful when guided by people of discernment and good will.
Even at their very best, scriptures lack the ability to acknowledge the reader, and therefore can not adjust emphasis and course to his or her benefit.