Those analogies aren't good because the outcome is not randomized. That's what makes things addictive and dangerous (especially for children). I think it's ver

Those analogies aren't good because the outcome is not randomized. That's what makes things addictive and dangerous (especially for children). I think it's very easy to draw a line. When you pay money, the result has to be specifically given up front. It cannot be based on random chance. If you wan to buy a Pokemon card you have to buy a specific card (or a set with fixed cards included). If you want to buy virtual clothes for your avatar then you have to buy specific objects. If you want to buy a doll then you buy a specific model, not a random box.