This potential for utility in the future is because Africa's native grains tend to tolerate extremes. They can thrive where introduced grains produce inconsistently. Moreover, most can grow better than other cereals on relatively infertile soils. For thousands of years they have yielded grain even where land preparation was minimal and management poor. They combine well with other crops in mixed stands.
Some types mature rapidly.
They tend to be nutritious. And at least one is reputed to be better tasting than most of the world's well-known grains.