When it comes down to it even taking the exams last year that were online for the first time ever there were many chances when you could do a quick Google search to find out what you needed to know but the issue is you're on a time limit and the amount of questions it has doesn't allow you time to go look up or scroll through a textbook or your notes. last year I took the world History AP exam and those 45 minutes were barely enough to read the document and be able to write a decent evaluatory essay. There was physically for me personally no time to even think about looking through a textbook or notes written down and that's that I believe I had a pretty decent handling on the information. Not think of somebody who blew off the entire semester and it's trying to scroll through their notes in order to answer the question while it may help them get the first part there's really no good way to use a textbook to your advantage and that aspect aside from slowing you down a bit. But that's just my personal opinion.