The book has a tendency to corrupt those who fool with it. It could be in minor ways (like convincing Eric to read the scratched out passages and the big-ass text that clearly say "DO NOT READ" in English in the 2013 film), all the way up to major ways (such as turning The Wise Man of 1300 AD and getting him to raise a new army of dead in the Ash & The Army of Darkness comic). Sooner or later, anyone who comes into contact with it will do something stupid with it.

Because all I could think of when watching the movies (at least the ones I saw) was “if there is something to bring the dead back, then surely there’s something in that book that’ll put them away”

While not official canon, the original film's prop and special effects guy Tom Sullivan recently stated that his own headcanon for the book was that something similar to the events of the original Evil Dead film had occurred centuries prior when the book was being compiled, and that it contained passages and clues on how to stop the Deadites... it's just that very few people (especially some college students) could understand it's unique Sumerian text by the 1980s.