Answer:
The growth of cash crops in Africa are likely to increase economic growth and development in the areas where they are cultivated, because these crops respond to international demand, and do tend to have a higher price than other crops. However, it is to be seen if the economic flow of money from the cash crops reach the majority of the population, or only flow to the hands of a few people.
Enviromentally-wise, cash crops could be damaging to the soils, leading to soil depletion. They could also cause more deforestation because there is an economic incentive to clear out forest and replace it with cash crop plantations.