It is important because it's the difference between giving and recieving.
Explanation:
The definition of refugees is "people fleeing conflict or persecution". The definition of economic migrants is "movement of people from one country to another to benefit from greater economic opportunities in the receiving country". The United States, Canada, and European countries turn refugees away because they are fleeing conflict, could potentially bring that conflict or cause conflict to the new place, and don't give back in a major way once they are granted permission to stay. Whereas, economic migrants are, mostly, not fleeing conflict so the place wouldn't have to fear foreign affairs and consequences, as well as the fact that the migrants will, in some way, give back to them in a way that benefits the place in multiple ways or a major way (such as giving back in the form of exceptional work or labor). This is why they have policies that distinguish between refugees and economic migrants - they want to invite in the people that will benefit them whilst keeping those who won't benefit them out.
The answer is a virus. It has been a controversial topic. It is debatable which animal kingdom it belongs to. Virus' fall into the gray area because they require others to survive: to reproduce.
