What an interesting question!
I believe that animation is the ultimate art form. It's painting, sculpting, dance, rhythm, martial arts, music, photography, acting, filmmaking, and editing all crammed into one!
All human cultures have eventually relied on some kind of art in order to keep their history alive, with sculpting and painting probably being chief among them. Animation is still fairly new, but through 1930's Disney cartoons I can learn about a part of American society and culture that I have little to no real connection with from 2009. For example, Mickey's Polo Team from 1936 features such 1930's celebrities as Harpo Marx, Laurel & Hardy, and others. I think it's fair to assume that most kids today aren't familiar with the Marx Brothers, but they might get a little flavor of the comedy from seeing this short film. So, is Mickey's Polo team helping hand down history? Honestly, I don't really know. It isn't really teaching history, merely giving modern audiences slight hints as to what these comedians were like. Most of the jokes are very specific to the events of the day, and most of us wouldn't understand half of what they're talking about. Does that count? It's like getting a tiny bit of the flavor of the day, but without the context to help it make sense.
A better example might be the Disney wartime cartoons created to sell War Bonds during WWII or to help train the troops. I suppose these are passing down a bit of history, and from a unique point of view, but again, it isn't history that you couldn't find elsewhere, and as well done as these films were, I don't think many people would seek them out specifically for a history lesson.
I suppose animation is too new for a cohesive answer yet, but because I do believe that animation will continue to grow, continue to evolve, and continue to become more and more deeply ingrained in our cultures -- I DO think that in the future, there's a chance that people may look back on "ancient animation" to see what they can learn, the same way we might study hieroglyphics or Greek sculpture!
So brush up on your animation, gang! We need to impress those future animation historians!