Airport shuttle services are offered for a variety of reasons. Some people get transportation from the airport after a wedding, for vacation purposes, when they go on a business trip, corporate events, etc. Airport shuttle services can take you anywhere you want to go, especially for foreigners who have difficulty getting public transportation.
Hiring airport shuttles is much cheaper than hiring a sedan, limousine, or taxi. They can accommodate more passengers and you don't have to worry about your luggage not fitting in the trunk of the vehicle.
Ferry drivers are often well acquainted with most of the roads and landscapes in and around the city, and you are guaranteed to get where you want to be safely.
If you are traveling in a group, it is better to hire a transport service because taxis are much more expensive. If you are on a business trip or on vacation, the shuttle will arrive directly at your doorstep.
You won't have to worry about being late for a seminar and that sort of thing. The same applies when you return. You will find the full shuttle service just outside waiting for your arrival.
Another advantage of using airport shuttle services is that the rates are usually low. This means that even if the shuttle gets stuck in traffic for hours, you will not be charged more.
Whereas in public transport one of the main disadvantages is that you have to carpool with many other travelers. The shuttle makes several stops to drop off travelers, and if it's the last one, you may be out of luck.