Access to its contents is limited by the poor design. Unless one has a narrow rake, it would be difficult to get the money from the belly of the pig. Perhaps that's the idea: it's Mr. Rich's way of ensuring that the money put in the pig stays there, and isn't squandered on a variety of meaningless pursuits or toys. But Richie is quite savvy with money, from all appearances, and perhaps this was a test: if his dad was profligate enough to buy him an enormous pig-bank, he would use it to set aside money, so he had something in case Dad's fortunes went south.