When I used it in November, it was not reserved seating. The only advantage was you didn't have to wait with all of the other people in the giant line that was formed. I get really upset when I'm packed in the middle of a really large crowd and everyone is bumping into each other so avoiding that was a nice aspect to it and kept me happy.
Other than that, I really felt like it was kind of a wasted FP. The area that they dump you into is the same merchandise, food and drink area that everyone gets put into before entering the auditorium.
I wound up not getting a FP for it on the trip last month and I got great seats close to the center of the auditorium in one of the front rows.