Looking at this from an economic point of view only, genetically modified crops are a benefit to a country's economy. So far as we know at this point, GM crops are more productive without any proven negative side effects that would harm an economy.
One thing that improves an economy is improved productivity. That is, when an economy can produce more goods using the same amount of resources, it is better off. GM crops can do this because they produce higher yields than regular crops and/or they produce a given yield with less need for things like fertilizers or pesticides.
Please follow the genetic-article link below for a number of essays on the effects of GM crops.