An encyclopedias purpose is to make information available quick. Just as a comparison, as kids in the 70's, 80's we had nothing comparable to Wikipedia, we were relying on word of mouth mostly. We believed in urban legends, myths and all kinds of half-information that we heard from people. Now it takes two seconds to find out whether it's true or not. These kids nowadays are way more educated than us back in the days if they use Wikipedia (& common sense). Do you think that the encyclopedias you found in the libraries are not full of mistakes? We were actually having competitions finding them, there was plenty. In Wikipedia at least it doesn't take a decade to correct mistakes.

If you need quick information about a country (population, gdp, transport) then Wikipedia is perfect, if you need to know details about the history of a country, then you can dive into details and make long researches. I'm also using Wikitravel nearly on daily base to organize my trips. I can tell you that it proved to be extremely useful in real life. You can bash Wikipedia all day long if you want, but until there is real alternative (which I highly doubt there will be in the near future), it's kind of cheap to criticize a free service.