The main purpose of Valet is to reduce unproductive time. How it will work depends on the station, volume, number of employees, service area, and those kinds of things. Most of the gains come from altering start times. Take a station with a roller belt, for instance. Those who are at the very end of the belt will start later instead of standing there 5 to 10 minutes waiting on freight to roll down.
It takes some getting used to but once people stop fighting it for the sake of fighting it and learn to make proper use of it, it's not bad.
Small stations already pretend to do a lot of stuff, hence the reason they're so inefficient.