It teaches you to guard your stuff? That's ridiculous! As far as I'm informed of, Minecraft isn't the least bit like reality. I mean, how many times have you seen on the news, "Man is eaten by zombie because he could not defend himself with 'diamond sword'"?
That's what I though. Never. All Minecraft will teach you, if you say you play it so you can guard you stuff, is to murder people with swords, bows, and fires if they come anywhere NEAR you.
And as for the infinite world that you mentioned, why not do it in reality and get even more from it instead of spending hours in front of your computer screen? Sure, money and time may be a problematic factor in that but Minecraft only generates what kinds of environments? Deserts and plains and forests? Well say hi to California who meets all these needs. so "pounce" snap out of it and meet reality! :D