Do you think this was specific to your reading group? Or do you think you would have found most any of them to be a waste of time?
I haven't really seen one that seems extremely exciting, and was wavering on whether to do it or not.
Separate, but related, question: Are reading groups available 2nd semester?
So, oddly enough, I never talked to anybody else about reading groups, so I have no feel for how good/bad any of the other ones were. If I could go back in time, I wouldn't have done mine, but your mileage may vary dramatically.
I think the creation of the reading groups had a fairly noble goal behind it. 1L can be quite the intellectual drag, as you suddenly find yourself with no electives 1st semester taking the same standard classes your entire section is taking in fairly large class sizes in lecture format. Reading groups, theoretically, should provide a sort of outlet where you can shortly learn about another topic that interests you, meet people from outside your section, and not have to deal with the stress of it being graded. Plus, the smaller seminar size would be really refreshing compared to the large lecture courses; I know of one undergrad that offers first-year seminars precisely to counteract the larger lecture course sizes of intro courses, except there the course is graded. Meeting people outside your section is always cool; I'm still friendly, but never became close with, some people from my reading group. And theoretically my reading group could have been amazing, but I wasn't a fan of the way my professor ran it. I actually think the fact that it's not for credit adds some level of stress--it takes up time to prepare, and that can be stressful when you have other readings for graded classes pressing.
Overall, if you see a reading group that really strikes your fancy, I'd say go for it. But if you're sort of meh about the topics, feel free to pass without worrying that you're missing out on part of the quintessential law or Harvard Law experience.