Towncars and taxis drop you off in front of your airline's counter. If your airline has curbside check-in, it will be right where you are dropped off. For the past few years, I have only booked towncars one way, from the airport to my hotel. I want a grocery stop. Also, I do not want to be on a bus which might make other stops before I get to my hotel. And some of my trips were for conventions, so I stayed at hotels near the convention center and was not eligible for Magical Express. So I find it beneficiary to take a towncar from airport to hotel. But I don't think there is any benefit to taking a towncar, rather than taxi or Uber, from hotel to airport on departure day.
Back when I booked round trip, I would tell the towncar company (or enter on their website) the time of my return flight, and the towncar company would give me a pick up time of two hours before my flight.
When I went to WDW last month, I used Tiffany Towncar from airport to hotel on arrival day, and Uber from hotel to airport on departure day. I saved $25 over using Tiffany Towncar round trip.
I think Tiffany Towncar and
FL Tours are comparable in terms of service.