Answer:
Religous purpose.
Step-by-step explanation:
Egyptians widely believed in afterlife and that when you die, you wouldbring your body and possessions into the afterlife to live happily if you were seen as a good person. Many kings and queens were seen as gods and godesses. So they'd have huge tombs (the pyramids) and would have their body perserved very well (mummies). The egyptians believed in everyone having Ka, which was spiritaul. When the physical body died off, the Ka would live in the afterlife forever. The pyramids (their tombs) could help them reign in the afterlife as Ka.