For a kid growing up, Encarta was far superior to anything Wikipedia offers today.
Sure, Wikipedia wins in sheer volume but that's it. Encarta was a well curated collection of knowledge that was consistent and perfectly suited for its audience.
Okay, let me link to a pastebin with the entire contents of my hard drive in binary form (with sensitive data removed, of course) and you can give it to your niece to read. Surely that information is more useful than a children's book on science. More data is always better by definition.
That is not the correct use of "by definition." More only means more, not better.
... In that Empire, the Art of Cartography attained such Perfection that the map of a single Province occupied the entirety of a City, and the map of the Empire, the entirety of a Province. In time, those Unconscionable Maps no longer satisfied, and the Cartographers Guilds struck a Map of the Empire whose size was that of the Empire, and which coincided point for point with it. The following Generations, who were not so fond of the Study of Cartography as their Forebears had been, saw that that vast map was Useless, and not without some Pitilessness was it, that they delivered it up to the Inclemencies of Sun and Winters. In the Deserts of the West, still today, there are Tattered Ruins of that Map, inhabited by Animals and Beggars; in all the Land there is no other Relic of the Disciplines of Geography.
purportedly from Suárez Miranda, Travels of Prudent Men, Book Four, Ch. XLV, Lérida, 1658
That's only true if your brain is perfect and consistent at absorbing and verifying information. Even then, it's unnecessarily reductive.
If you have an enormous amount of information, but know that some unknown 10% of that information is inaccurate (at a facts level, not just in a "I don't agree with the presentation or perspectives portrayed" way), that's dramatically worse than having slightly less information that you can be fairly sure has been (at least factually) verified.
Same with writing quality; a huge amount of information written in a way that your brain can't absorb efficiently (whether because it's in a foreign language, written incoherently, or interspersed with profanity and editorializing) is less useful and worse than less information written in a clear and consistent style.
Sure, Wikipedia wins in sheer volume but that's it. Encarta was a well curated collection of knowledge that was consistent and perfectly suited for its audience.
More is not always better.