I've also been doing this for the past few months. Only difference is I have to get 10-12 hours for some reason. So it turns out to be either 12pm-12am, 3pm-3am or 5pm-5am. All of which are great.
I think the greatest merit of doing this is not being tired when you start your day. When you wake up at 8am and go to class or work at 9am, your brain just hasn't had enough time to wake up. I've failed many exams for this reason. Now when I take my exam, I've already been up 8 hours and I even get all that extra time to study.
This is true! It also helps the work(/school?)day go by much quicker, since the first half isn't dragging due to grogginess and the second half isn't suffering from the poor mood the dragging first half generated.
I think the greatest merit of doing this is not being tired when you start your day. When you wake up at 8am and go to class or work at 9am, your brain just hasn't had enough time to wake up. I've failed many exams for this reason. Now when I take my exam, I've already been up 8 hours and I even get all that extra time to study.