The Greeks learned from the Africans, not vice versa/ Kemet Mysteries Schools come from us, as does the tradition of a tiered learning system. Although it is unspoken, the Greek lettering became associated with learning and academia for this reason. Because of the Western attempt to erase all of what we have given civilization, the Divine Nine, keeping with tradition, just went along with the established system of using Greek lettering, is my guess. It's kind of like how we use the Arabic numeral system. I don't know why everyone agreed to use those numbers, but we know Africans were the first to develop maths. ->>> The Lebombo Bone: The Oldest Mathematical Artifact in the World – African Heritage