Advantage over taxis: you know the fare in advance. You can budget your journey.
No loss of time thanks to pre-payment.
As soon as you arrive, as soon as you get on the train or plane or at home!
If, however, during the journey you need to change the itinerary of your trip or the duration of your provision then inform your driver as soon as possible. The latter will adapt to your request as much as possible. For example, if an appointment ends later than planned, your driver will pick you up later or wait for you.
Additional billing will then be set up according to the nature of the change, the schedule or the kilometres.