There was huge value in thumbing through these as a child. We could never afford the set, but I had used copies of individual volumes and I spent many, many hours reading random topics. You just don't get that kind of discovery in an online version. Maybe you could, but you don't.
Seriously? YOU don't? You've obviously never experienced the Wikipedia death spiral: 30 browser tabs open all on unrelated Wikipedia pages. It was dangerously close to an addiction for me at one point and the amount of random crap I now know it irritates me I'm still so poor at pub quizes. There's probably some Godwin's Law equivalent where once you've opened a tab relating to Hitler or the Nazis, having started off on an article about Bengal Tigers, you know it's time for bed.
The problem is that you're selecting the topics. The value of a physical encyclopedia is that they've selected the topics and you're browsing them at random.
