Even for very long distances (where flying is almost mandatory unless you are ready to spend weeks traveling) trains make things easier.
For example I'm living in a small village in the south east of France and I will be traveling to the carribean in summer for family, I will be walking to the train station is my village to take the train, 2 changes later I will be in London from where I'll take the plane to cross the Atlantic.
Same thing on the way back but with a night train.