Why should you care about how our history and the history of our parents and grandparents and great-grandparents--the history of the long twentieth century, 1870-2010--will appear to people five and more centuries into the future?
First of all, it makes a very good story. And it makes an even better story because the story is real. We are gossiping animals—we have evolved to like to tell and hear stories about what is happening and has happened to our friends and not-friends. We like this so much. We like this so much that out of our time that is not spent hewing wood and drawing water we spend a very large chunk gossiping and listening to gossip about not our real friends and not-friends but about imaginary friends: there is no such person as Harry Potter, and so there is no strong reason to care about what happens to him or to Severus Snape, but we do.
And the best stories to tell and listen to are the real stories, about real people: they have a depth and an import that fiction cannot reach.