What is wrong with the Lotus Casino in Percy Jackson and the Olympians: The Lightning Thief?

The Lotus Casino and Hotel in Las Vegas is a place created by the lotus-eaters so that anyone who darkens its doors will want to stay there forever. Guests are provided with everything they could possibly want, from highly addictive games to good food to luxury accommodation, all paid for by plastic cards with unlimited supplies of credit. Everything has been designed to make sure that no one will ever want to leave.
But this is no ordinary casino. For one thing, those inside never age while time outside accelerates. At first Percy, who's there at the casino with Annabeth and Grover, thinks it's a fun place to hang out. But pretty soon he realizes there's something not quite right. As he looks around the casino, he notices that there are people from many different time periods. As we've seen, this is because people stop aging once they've set foot inside the casino.
Percy snaps out of the trance that looked set to keep him in the casino forever and high tails it out of there, taking Annabeth and Grover with him. Once they've safely put the Lotus Casino behind them, they suddenly realize that they'd been there for five whole days.