And that is precisely why, unless you go between two directly connected cities, car is even more convenient than train. You don't happen to live in the train station in Paris. And neither do you happen to stay at the train station in Berlin.

Google Maps tell me Paris-Berlin is 9h35 minutes by car. I can now leave at the exact time I want. Maybe pick up something on the way by making a little detour. And arrive at my destination and have a car there.

I did that just yesterday (a road trip from Luxembourg to the french riviera): 960 km road trip (600 miles). Closest train station is a one hour drive. Closest highway is a 45 minutes drive. Closest airport a 1h30 minutes drive.

And of course once at my destination I then get to use my own car, not a rental one.

P.S: No security check lines. No being packed like sardines.