I know its hard for people who think gaming is the center of the universe to think outside the box, but here is a tip...Microsoft couldn't give shit about minecraft as a game IP and that is not what they paid 2 billion for.
When they want is people who play Minecraft using microsoft accounts, which leads to microsoft services. Minecraft is everywhere, on every platform and once this deal goes through, in order to play it on any console you will need to log in with a microsoft account. Buying minecraft is a gateway for them to get iOS, Android, PS3, PS4 users to create microsoft accounts and potentially utilize other microsoft services and advertising.
Facebook paid something like 14 billion for WhatsApp for this exact same reason. They have a messenger that is as good if not better yet they blew 14 billion on whatsapp.
I am confused. Whatsapp requires a facebook account?