With truly autonomous vehicles, you can have a radically different logistics for goods, delivery services etc. You can also have specialized "sleeper cars" that get you to your destination overnight, fresh and ready.
Self driving cars can also park themselves somewhere out of sight and stop clogging inner cities.
We can't go straight from level 2 to level 4 without some real effort, and it's not exactly helpful when new level 2 systems can't even handle curves[0] or will continue to drive for you when you take your seatbelt off[1].
0: https://youtu.be/GCRNYP5Qg34?t=321
1: https://twitter.com/MinimalDuck/status/1388557772921344005?s...
Trains have had this capability for decades, and that is a very mature technology, with the upside of also carrying far more people at a time than a car-based system would.
First of all, trains shake a lot. I could at best take hourly naps, it was better than nothing, but far from optimal. The loud proclamations of station speakers whenever you stop somewhere do not help your sleep either.
Second, night trains are a paradise for opportunistic thieves. Yes, it is a solvable problem, but I haven't seen it solved.