Since the Wooden Ushabti Box Has lot of Art From outside from book of dead since all scenes outside is from book of dead for mummification cermony such ushabti box they put at grave to protect Grave of King since they thought the king after death will have same life like Earths Life also such ushabti box and ushabtis inside grave to work as servant for dead since they thought dead will eat drink clean marry since they put such ushabtis to clean prepare food water for dead. Since it has Big Ushabti which were used to work as Servant and minions for Dead it will cook clean farm for dead since they thought dead will have another life same like earths life since it has lot of Art from Outside also was taken to Grave After Death.