Please read the following article for some good perspectives on how Minecraft is an essential and valuable tool for kids. (It’s also got a great Dr. Strangelove reference in the title!):
https://www.yahoo.com/tech/five-reasons-parents-need-to-stop-worrying-and-learn-to-83359212475.html
http://www.primarycoding.com/minecraft-educational/
And this is a good primer for how the game actually functions:
http://www.huffingtonpost.com/jason-p-stadtlander/a-parents-guide-to-minecr_b_5223515.html
There are literally thousands of pages of writing about this game (not to mention weeks and weeks worth of Youtube clips), so please take some time to get acquainted with this movement that is sweeping across the educational landscape.