At least in America, millet is often used for bird food. I don't begrudge the birds their food, but I would like to see people eat as well as they do.
It can be used in "dry farming", grown where other crops need irrigation, and it thrives on poor or marginal soil. The attached video shows how nutritious it is.
So why don't we eat more of it? Maybe because it's growing uses less of the chemicals we seem to be dependent on.
How do I like it? Cooked in a little water, like oats, topped with butter and a little honey. How sweet it is.