Many FBOs provide “courtesy cars” to pilots who need to make short trips away from the airport. However, this is not always an option. Sometimes the vehicles are already taken, or you need the vehicle for an extended period of time. So, the only other option in this case is to rent a vehicle. Enterprise is making that easier by providing a web site where you can enter the aiport code and it will list the FBOs that it knows about. Enterprise will then either deliver the car, or pick you up and take you to the office.
This may seem to be a small detail, but it shows that Enterprise has picked up on the number of pilots who could benefit from this.