A book about Africa is uniquely suited to D&D idea mining. For one thing, it’s unfamiliar. Your D&D group may have some medieval history buffs in it. Fewer groups have any Africa experts. I never learned about pre-colonial African history in school. (In fact, a lot of its history was entirely unknown until archaeological work in the last few decades.) As far as my familiarity with the subject matter went, the history in this book might as well have been the history of an alternate Earth. Which is basically what a D&D campaign world is: that plus magic.
After my reading, I didn’t end up with an Africa-themed campaign: I still have a typically Western European fantasy world. However, the interaction of these two milieus provided some interesting and peculiar details. The Plateau of Spirits and the Raid Year, the sacrifice of the Stag King, the roadside altars, the Wind of No Return, the Elves of the Ruins, and the dwarven soul discs give specificity to my campaign world.