Yes, the economies of home countries benefit from the migration of their natives abroad, because it gives the economy in the home country a chance to react to the people who move. If people move abroad, there will be new jobs available for other people that are left behind. Prices will rise and fall in response to their move. Economies are elastic and durable. People do not need to worry.
Yes, I believe that the economies of home countries benefit from the migration of their natives abroad from a cultural ties perspective. Generally, migration occurs because the individuals are seeking better education or living conditions. Often times, this leads to individuals in a family leaving family members behind in the home country. Therefore, when an individual achieves the higher education and is presented with better opportunities, he pursues some sort of money making career in the new country. This naturally leads to spreading culture and awareness of the individuals native country, while at the same time the individual feels the obligation to help his family or community he left behind by sending money or providing some type of business opportunity.