I'm an IDine member as well as an airline member and get books for all of them. While you're right that checking the web is useful (and some restaurants you have to visit the web for credit) I find the book(s) most useful when I'm on the road. Also I try (am not always succesful) to check before I head out of town - if I'm going to be somplace for a few days - which restaurants have ZAGAT listings and select those with good ratings. I then make notations in the book so I remember which are worth visiting as circumstances or culinary desires change.
You may want to call customer service if you want the book and aren't receiving it.