Reason #1: After they finish their higher education in that country, it's easier to settle there, since they can get a job right out of College in that country. (atleast that's how it is in USA.)

Reason #2: Freedom to do what you want. For example: you have be in a Live-In Relationship while in College and not care abt what anyone thinks, that is, IF any1 thinks in a disapproving way. That's not possible in India.