Skill Rating is often useless given safety rating is primarily used for matchmaking. A possible use for Skill Rating in online races would be to use skill rating as a backup to qualifying times for drivers who do not post qualifying times. After qualifying times fill out the top spots, skill rating from highest to lowest sorts the rest of the starting grid.
High Skill Rating should reflect a general trend toward shorter lap times and faster drivers. Those driver naturally should start towards the front of the grid. A faster driver starting near the back, while an admirable challenge, may contribute to added chaos on the track.
This could be a useful feature for those races that start with very short practice times. Often when finishing a race and continuing on to the next race, practice times can be very short, sometimes not even enough to make 2 practice or qualification laps.
I know some people like the added challenge of weaving through the pack to go from last to first, but this is probably not very compatible with proper racing ettiquette. Multi-class, offline, or private lobbies would be better suited to this sort of racing. Faster drivers should be at the front of the pack at the green flag in a regular race.