... , because the one thing you really want when buying a shelf of useless books is even more useless books to litter your coffee table.
I really cannot think of any occasion where the two-paragraph overview from a printed encyclopedia ever helped me accomplish anything. If I needed to study something specific, I went to the library and borrowed a few books on the topic. Encyclopedias are what you read when you don't really care all that much about the subject.
I pity anyone whose knowledge of the pre-web role of encyclopedias is limited to the poster's comment.
In 1968, my parents acquired a set of Enclopaedia Britannica ( == Yes that is the correct spelling). This was just prior to my experiencing a soccer injury that would confine me to bed for most of the next two years. I spent most of that time reading EB. (Yes, I also went to the library every week.) My time with EB did more to prepare me for college than any other single aspect of my high school education.
(And I came from a household that housed more than a thousand books and multiple sets of competing encyclopedias as well.)
Your "two paragraph" assertion is misleading. I still remember reading a biography of Rene Descarte that went on for pages. The article on World War II was even longer. Also, encyclopedias were never meant to be one's only source of information. Just a "jumping off" point in case the reader needed a starting point. This is the same way Wikipedia is used today. Need basic information? Use Wiki. Need more? That is what the iPad, Kindle, Nook, and the library are for.
Many years later, EB became one of my clients. It was during that experience that I learned that almost every article was written by a college professor likely to be an authority on the subject and proofread by another prior to publication. That many articles were also written by experts in their field (i.e. Albert Einstein authored an article on Physics in one edition) is also overlooked by the poster.
When my own daughters needed a resource in the early eighties, I did buy the Encarta, Grolier, and much later, the Britannica discs. In the internet age, my sons have no need for any of these.
But just to rant because one did not sit still, read, and appreciate this wonderful resource for what it was, is more a reflection on the poster and less a reflection on the value of such tools prior to the internet.