I'm being a little sarcastic here, but my 23 trips to Disney have meant I know more about the parks, Disney hotels, and miscellaneous attractions in Orlando than anyone else on my block and can make an instant connection with any Disneyholics I meet. // I'm even the person my husband relies on and goes to first for crossword puzzle questions about Disney topics. // Watching Disney movies will help more with this last one than Disney parks, but I've also improved my skill with the "Disney Scene It Game" from doing certain Disney attractions multiple times, and on rare occasion can even beat my son, nieces, and nephews (Without my park educational experiences that would never have happened.).
On a more serious note:
Learning something new is one of life's many pleasures and Disney is a pro at doing this in an entertaining way. Other Orlando attractions and nearby attractions to stay competitive and in business have really upped their ability to do the same: SeaWorld // The Titanic Attraction on I-Drive // Kennedy Space Center are three other favorites of mine. The Kennedy Space Center tour by the way used to be sooo boring / horrible really -- but they have really improved their act -- learned something by their nearby theme park pros and the tour now is a delightful learning experience even for someone who isn't a space enthusiast.
But let's get real -- the true reason for most of us for an Orlando/Disney visit is to have some fun. // The whole more educational than school thing is probably true of any travel experience (especially for the child or adult who hasn't had/ doesn't typically get lots of travel experiences). For travel we've done Disney would get a ranking somewhere in the middle for educational value for us. Typically I think of travel to experience other cultures / meet the natives / find out how other people live at the top of my list for being eye opening and enriching. And really an exchange student experience or overseas living experience does this so much better than a trip -- but a little trip is all most of us usually have and some trips can do a little of this. And I'm sorry -- sure it is educational and fun to talk to people who work at Epcot who are from other countries and speak to people from Africa at the AKL (It's wonderful that Disney has people from the actual countries as Cast Members and they love sharing information), but it is not in any way shape or form the same experience as going to that country IMHO. I'd probably rank visiting famous historical sites ahead of Disney in terms of educational value too (just my own thoughts about what we've learned on trips). And then there are trips to Natural Wonders (e.g. visiting National parks etc. -- great educational ranger guided hikes/talks -- learning some camping skills but probably less educational than an Orlando trip overall, but awe inspiring to commune with nature a little.
We and many familes have always done our travel when school is out. Our school district has 14 different full week off when you include Christmas, Spring Break, and Summer, so plenty to choose from. But I do realize that some families do have their kids miss some school for travel, as that's what works best for them.