Historical magic: the seated statue "stands up"
Since the Egyptian belief system, contained concepts framed in a world of magic and a formal framework of art expression, the block statue had a magical purpose. Obviously ideas evolved, but eventually the idea came for the statue that it was always – seated in place, and at a moments notice, the individual could stand erect and "go out into the day." This concept is quite similar to the Book of the Dead, where the individual is:
"returning, and entering..(to/from cemetery Neter-Khert)..the daily returning for events wonderful, to the loved, created habits, (all), sitting in the Hall, returning as a living-soul. Chapter VII, lines 1-3.5. (The Book of the Dead, subtitle: The Coming Forth by Day.)
The deceased individual Egyptian person returns each day, to perform their usual daily life duties. It is also equivalent to the earlier concept of the false door, where the ba-soul returned each day, to find the food offering.