Have you heard of gamification? It’s something commonly used in workplaces now to make people more productive. Turn work into a game, people enjoy it more, and they get more things done.
Plus, the difference with a hack and slash or first person shooter vs Minecraft is that minecraft structures stay. They started with nothing and created something. That’s work. It might be fun work but still, it qualifies.
I could be wrong of course, but this is just how I’m thinking.