The first reason for studying abroad is for learning. However you can argue that students also can study in their own countries. The fact is that studying abroad is effective way to learn the quintessence of advanced countries and learning the experiences of these countries. It is true that one country which wants to develop must learn experiences of countries especially advanced countries. That is why the great emperor of Russia in the 17th centrery Pitrot had gone to the Nertherlands to work as a worker in a ship-making factory to learn new technology; after learning he returned home to turn Russia from a backward, weak to a powerful country. Japan under Meijing rein sent many students to the west for learning for the sake of modernizing the countries and learning experiences of development of western countries. It can be said that studying abroad is the best way to learn knowledge, experience and the quintessence of the country where you are studying. Students who learn abroad are, therefore, more appriciated than students in home and their future is guaranteed.
Nowadays, in the context of globalization, exchanges between countries are more regular, information around the world can be accessed more easily but studying abroad still remain the most effective way. People can directly see what the country has done and can approach to a new way of thinking. They can live in the real environment, sense directly how things are operated.
More over, studying abroad is also the chance to explore more about the world, about people, culture, landscape of a foreign country. Those students studying abroad can have chance to travel and contact with native people. As a results, people' mind will be broadened very much.
Besides, there also remain many difficulties for studying abroad, namely the differences between two cultures, linguistic challenges, the nostagia and many other things which can happen when studying abroad. But, I think these difficulties can be overcomed for the long term goal of learning. These challenges can even urge them to study better.
In short, study abroad is really exciting in learning knowledge and exploring the world.