As the wiki article linked notes, most places in Africa didn't have a sustained bronze age. This isn't some 'crude attempt' or anything, it's recognition that technological development is not always linear. Africa came out swinging on iron bloomeries before just about anyone else. The invention and spread of the bloomery in Africa meant that they never went through a sustained period, like Europe or China, where iron was hard to refine and work, but bronze could still be handled by more primitive furnaces.

Bronze is just not worth it, except for decorative purposes and the like, if you can smelt iron.