What's that, a 3 hour flight? Hard to get too uncomfortable in a plane if it's only 3 hours. I suppose if you're not in a hurry and want to take a car the train is useful. But if you're flying for a 5-7 day vacation losing two days isn't worth it. So each has it's pros an cons.
OTOH, with the Auto Train, I breeze into the terminal, my car is rolled aboard with all my luggage (without weight limitations) and a pair of bicycles on the back, I simply board the train at 4 p.m. without having to wait in line or take off my shoes and belt. I then enjoy the trip, get off the train after breakfast, and I'm on the way in my own car by 11 a.m. the next morning.
Sure, I lose a little time, but I look forward to the train trip and sleeper car as I have never done for air travel in a long time.