Khufu's solar boat comes into the light as its burial pit is opened

They were assembled to witness the lifting of the 41 blocks that have covered the pit of Khufu's second solar boat for the last 4,500 years, and the announcement of the start of the second phase of the boat's restoration project.

Japanese Archaeologist open the boat pit next to the Pyramid

The boat was discovered in 1954 by Egyptian architect and archaeologist Kamal El-Mallakh, together with Zaki Nour. At the time El-Mallakh and Nour found two boat pits during routine cleaning on the south side of the Great Pyramid. The first pit was found under a roof of 41 limestone slabs, each weighing almost 20 tonnes, with the fact that the three westernmost of the slabs were much smaller than the others leading them to be interpreted as keystones

On the walls of the pit were several builders' marks and inscriptions, including some 18 cartouches containing the name of Khufu's son Djedefre. This suggests to many Egyptologists that some parts of his tomb complex were not completed until after Khufu's death. One scholar, Vassil Dobrev, has theorised that the two boat pits on the south side of the Great Pyramid were built by Djedefre as a gesture of piety connected with the establishment of the local divine cult of his father, founder of the royal necropolis at Giza

Yoshimura told reporters that while the fillings around the sides of the covering stone were being cleaned, the team uncovered the cartouche of the Fourth-Dynasty king Khufu inscribed on one of these blocks, and beside it the name of the crown prince Djedefre.

Earlier another solar boat was taken from its pit and assembled it is shown below



Wiki summary of the first Solar boat of Khufu

The question is:

Why did Khufu's son bury this boat (among others) as a sacrifice next to this pyramid? Why not his own?

A detailed analysis of the first boat found

Boat