I'd go one step further and say it has to do with engagement.
If you find the book/movie pointless the first time, no amount of reruns will change that. On the other hand, if you loved it and made you think about the issues it raised, it might be worth going through it again, but a big part of the extra deepness you find in the rerun will be placed in there by your subconscious mind.
Some things are simple enough that once or twice through and you have all that needs to be had.
Others are deep enough that you can discover and learn something new each time.