......Who would have needed such a standard?.....
Now think on that....who needs standards? merchants and customers, especially those who deal in products like grain or maybe beer.
It is by the way, plural because other pyramidal standards are noted, including length and lattitude.
We sell grain by the bushel, a holdover from some ancient standard of measure. Strangely believe it geodesic measurements are pretty much the same today as then.
The need to resurvey Egyptian fields after frequent Nile flooding is often cited as a reason for development of Egyptian mathematics. However, it might be noted that Egyptian math was not highly developed. That happened in other regions such as Greece, Persia, India. The level of knowledge of the planet and geometry in the Great Pyramid is high no doubt, but whether it was Egyptian at all is in doubt unless you ask the current Egyptian curator of antiquities Aiwass.