Video games are one of those mediums like books, movies and plays that you get as much out of it as you're willing to take away from a game.
Most people mention the historical aspect, especially with games like Assassin's Creed, however that's not quite accurate or even fully explains the potential of a video game.
Video games have the ability to enable learning. When we talk about enabling learning, we are talking about the ability to get the player to learn on their own terms, not because they have to, but because they want to.
Assassin's Creed for example is historic, but not necessarily accurate historically speaking, most mediums like movies and books (and video games) rarely are, but they can invoke what is known is tangential learning. Tangential learning is when a person hears, reads or watches something (like the Civil War in Assassin's Creed), and it gets them interested enough to look up more about the topic themselves. We've all done this, whether we are aware of it or not.
A more anecdotal example of how video games teach are players who talk about learning another language in order to play a game. A lot of players where English is not their first language, will talk about how they learned English by playing video games that could have only been found in English. There are probably Japanese learners as well for this same thing.
Beyond just learning facts, fans of video games (and really any fandom) have taught themselves new skills to create things for that fandom, or to be better at that game. Other examples include.
Any time a player has crunched numbers for Pokemon.
Any player who has made props or costumes
Any player who has taken time to write fanfiction or a song
Any player who has learned to play a song
Any player who has debated on a game's timeline with other players
Any player who has taught themselves to draw for fan art
And the list goes on, players who go beyond the game, a game they've played will communicate, make, produce, learn, read, write, draw and compose for that game they have come to love. All these activities are giving players skills that go beyond the game, which is why I said it depends on what you're willing to take away from it.
However, if you want more information on just educational learning in the traditional sense, my recommendation is also to check out Extra Creditz on Youtube, Their writer James, who is a video game developer and right now a video game consultant have done many videos in regards to education. In fact James is right now doing a campaign called Video Games for Good.
Also check out PBSIdeal Channel they did a short thing about education and Minecraft, and check out the episode after that one because a lot of responses to the Minecraft video included more source material about video games and education.