They do serve a purpose -- pumping and dumping dead coins that can't actually be withdrawn from the exchange. I didn't do my research and sunk about $100 into one. I'm technically up $20 on it (if converting to ETH/BTC, which I can't actually do because there's too many other sell orders at the exact same price necessary for me and others to make a profit ahead), but would be down as soon as I converted it to doge and paid the transaction and withdrawal fees.