If you think about, why are we allowed to up vote our on posts? That's like owning a store, pulling a dollar out of the cash drawer, buying something for that dollar, putting the dollar back into the cash register, closing it, saying an incantation, opening it, and voila, suddenly there is $1.10 in the drawer.
Do that enough times and you end up with a drawer full of money. But it doesn't help the overall economy any. No movement of "money" between participants for this magic money drawer increase.
It's almost like being a counterfeiter if you think about it.