We have free trade, but no open borders. Yet it has caused huge benefit to humanity. So I would change your statement as well. Free trade is a huge benefit fo

We have free trade, but no open borders. Yet it has caused huge benefit to humanity. So I would change your statement as well. Free trade is a huge benefit for humanity as a whole. Open borders may or may not be a huge benefit for humanity, as we have not tried it yet. The current economic migrant crisis will be a good starting point for an investigation and we will see if they integrate well.