The point is that they are not going to make a change that inconveniences the vast majority of their customers, while increasing the labor required to serve those customers, and at the same time maintain a separate infrastructure for the vanishingly small number of clients who happened to book one specific class. Either everyone goes to the counter or nobody does.

If my specific reservations says to skip the counter, pick a car, and drive away, that means that there are keys in the vehicles - which means that there are manned gates. The fact that Emerald Reserve is "different" than EA/ES is only relevant from a "where to find your car" standpoint - they are still all in the same physical space and still need to leave the garage through the same manned gates.