There can’t be that many guests staying in Deluxe resorts, can there? As a percentage of the total day’s crowd, I would think that it has to be very small. So it seems to me like you’re getting your own mini After Hours event at no additional cost. (Leaving aside the mark up for Deluxe rooms to begin with.).
I do, however, get the point that everyone gets in line for the headliners at closing, and thus the benefit of this perk might be less than it first seems. If you are staying Deluxe and want to ride FOP, the whole hour might be over before the day guest standby line has even cleared. I wonder if Disney will allow Deluxe guests to use the fastpass lines, as they have sometimes done with DAH. That would solve the problem.