1.- I can buy Cash with my phone and my parents won't notice because I can recharge it anytime at a convenience store.
2.- It can all be kept away from my parents because my mom already knows about the Marketplace and she would kill me if she knew I have spent IRL money. (Did spent quite a bit, I'm talking about $10, but I'm leaving and I'm not spending anything more for 4 months)
3.- I can sell my cash shop stuff for massive amounts of gold 3nodding