1)Benefits for writing sat is that because sat score  it is globally excepted 

2) If you have less score in academic having good sat score will balance you academic score

3) If you get good score in sat you get scholarship this one of top most benefit of giving sat

There are many prestigious college in India where you can get admission through sat score for eg 

Iit or nit ,iisc through dasa counselling you can get this college

Some of private college birla institute of technology and many more