There was point in time where that truly felt like the future. Considering that we're now in the age of autoplaying, monetized "content" video nearly everywhere you go, it was nice to have only "primary source" video, aka stuff like the moon landing, or the MLK speech, instead of some nobody warbling on about its importance while splicing in stills of said video because they don't want to be in violation of the copyright.
The concept of finite, structured and bounded content is also extremely powerful in this era of overwhelming data, much of which rehashed and warmed over by various publications not to mention utterly infested with ads.
The concept of spending hours down a Wikipedia rabbit hole is not new, and it's one of the reasons I donate annually. But it first started with Encarta, and it's offline-only format has grown to be only more valuable as time goes on.