Reading books is a good activity, provided you're actually learning anything from them. Obviously, people who read a lot are in a position to contribute more positively to a debate.
If a discussion is going along and you're able to articulate ideas you've gathered from a book to illuminate the discussion, that's great. But there's another tactic which I call "book wagging".
Book wagging is when someone declares someone else in the conversation wrong, but refuses to explain why, claiming it's all in a book they've read. For one thing, it kills the conversation since it cannot now proceed until the "refuted" party goes and reads the book.
Cindy: I think we need to raise taxes.Carol now has the upper hand. She has established herself as better read than Cindy, and declared a victory in the debate. Bear in mind "Atlas Shrugged" is about 1000 pages long. The conversation is now dead until Cindy goes and reads all 1000 pages. If she finds that the book was not relevant to the case she was making, or that the arguments contained in it were not very persuasive, the discussion has been over for weeks, Carol is by then long gone and not accountable.
Carol: That's been completely proven wrong, you need to read "Atlas Shrugged".
A couple of times people have wagged books at me during the discussion of topics near and dear to me, so much so that I dug up the book and read it, only to find that it had no legitimate bearing on the topic being discussed.
If Carol really had read "Atlas Shrugged" (not really for certain -- people often wag books they haven't actually read) and it really did contain insights that would shed some light on the discussion, Carol probably would have been able to articulate some of them. The fact that she declined to do this and just threw a book at Cindy is a sign that this wasn't the case.
Sometimes a topic is too complex to be dealt with in a certain medium, such as an informal verbal discussion or a facebook discussion, and then it is a valid time to say "I can't explain it to you here, but it's in this book". But much more frequently, books are wagged as a disingenuous tactic of the intellectually bankrupt.