Pila Ku Jail is an intermediate grind-zone. Pila Ku mobs are primarily grinded for money and the map piece.  The full map when created allows a player to travel anywhere in the game and port back to the original location within the hour of the first port. The xp here is decent but nothing special. With that being said, this spot is decent, you can grind Polly's for better, more profitable rewards. Polly's is also one of the best spots in the game for xp.