I wouldn't say crazy, everyone believed that what they were buried with them was what they took into the after life... hence egyptians buried with jewels.

Its part of the ancient thoughts and the hold on life that they seek to maintain. Just like what the Chinese taoists/buddhists still do today where they burn paper effigies of maids, cars and houses etc.

In the past before paper was invented, many types of materials such as clay and terracotta was the preferred choice. He actually didn't want to die and use this tomb at all.