Pirate treasures are usually hidden, buried or considered lost. So is One Piece, which was left behind by Gol D. Roger somewhere on the Grandline.

The One Piece biscuit jar treasure chest on the other hand is far too beautiful to be buried. Although it is made of ceramic, the chest deceptively resembles a wooden treasure chest with iron fittings. The removable lid is emblazoned with the sign of the Straw Hat Gang. Depending on the contents, the treasure chest should always be within reach anyway. After all, what good are biscuits, chocolate or other sweets if they are buried somewhere underground? ;)