The pyramids were built to last for all time as a statement of the accumulated knowledge and technology of the Egyptian society, the glory of the Gods and pharaoh and possibly, not unlike the bible, a testimony to the human condition throughout time, for those who were trained in  the symbology.

Much of the culture of the society was centered around the recognition of the presence of 'living gods' which took the form of animals and other nature symbols and a strong belief in an afterlife,

Much of their adult time was spent in preparation for that afterlife and much of the work of the society was centered on preparing for the afterlife

What does it tell you about a society that renders human likeness to a flat symbol that creates oversized monoliths and temples with mathematical precision. 

That has a highly structured society, which survives for two thousand years, accumulating great wealth, knowledge and power, but keeps a large portion of their work force as slaves?

This society was an experiment in one man-god-king ruling everyone and everything within a strict social structure.

The architectural accomplishments of the ancient Egyptians continue to inspire to this day. 

The specific role of the pyramids did not continue beyond the Egyptian culture of that time, but the pyramid-temple, did continue in other parts of the world.