Cheap real world weapons testing. You blow up a few Africans to make sure the weapons systems can work in the field when operated by our troops before you buy a large contract supply of them from the manufacturer. It gives you honest feedback from the troops using the equipment and a realistic assessment of how effective the hardware is when deployed half a world away, and nobody gets hurt, ... excepting a few nobodies. /s
Whne you think about it, the Chinese will have every chance when black tribes begin attacking Chinese farmers. If black dictators start terrorizing Chinese farmers, the Chinese government can treat this as a chance to retaliate militarily in the viewpoint of protecting their citizens and interests. It would be the perfect testing ground for their military capabilites. They can then end up figuring out their strengths and weaknesses and find out what needs to be improved.