The idea is that if all or even most of the cars are being driven by computers, they can all talk to each other and coordinate the most efficient way for every car to behave in order to keep traffic flowing properly.
Imagine if you’d gone to LA, and every driver on the road was a perfect driver. No idiot cutting you off, or merging in front of you and slamming on his brakes, or tailgating you, or cutting across 7 lanes to catch the exit he almost missed, etc.
Traffic jams would be orders of magnitude better if the dumb apes driving through them would drive for the good of the system rather than selfishly trying to get the best advantage for only themselves. But you’ll never get people to do that voluntarily - the average human is too selfish, too ignorant, or both. That’s what a self-driving car grid promises to bring about.
The transition, when computer-driven cars are sharing the roads with the dumb meatbag-driven cars, is going to be rocky, and will actually require the self-driving cars to be smarter drivers than they will have to be once the transition is complete because they’re going to have to deal with all the unpredictable idiots that won’t exist on a 100% AI grid.
But once we’re on the other side, traveling from A to B will be a stress-free experience that will allow you to do things which are actually productive rather than waste time wiggling a circle back and forth while pressing on levers with your feet.
The transition between horse travel and car travel was pretty rough too. Cars spooked horses, horses got in the way of cars, and both camps despised each other.
Today, no one would think of going back to doing road trips in a stage coach, but plenty of people still use horses for recreational purposes. It’s better for the horses because now that they aren’t a required mode of transportation, fewer people own them, and so fewer of them are being abused by being worked down to the bone until they’re good for nothing more than a glue factory.
And it’s better for us because we get places faster and more covneniently. I certainly don’t lament the fact that I don’t have to stop in a random town and try to find a blacksmith to replace the shoe my horse threw, and I don’t regret that I don’t have to stop every couple of hours to let the horse rest, or feed and water it several times a day.
I certainly like the fact that if I want to go to my favorite race track, about 250 miles away, I can do it in one day, with time to spare, in air-conditioned comfort. With the horse, I’d have to take several days to do it, and even then it would be tantamount to abusing the horse, making it go that far that fast. And then once I got it there I’d have to be sure it had a good place to stay, food, water, and horse alarms weren’t a thing so I’d have to worry about some jerk stealing it… Cars are better!
I suspect in 50 years or so, people will look at human-driven cars the same way we look at horses now: They’re neat, and fun to spend leisure time with, but sitting in a traffic jam or taking a cross country trip in one or even having to rely on one for daily transportation needs would be antiquated and wholly unpleasant.