The real question is "what do you mean by 'it works fine'?" To me, the effects of suburban living are such that we don't treat people as people unless they're shrouded in a big rolling box of metal. Of course it'll vary from person to person and family to family. I think urban environments offer children much more freedom than corresponding suburban environments, while being safer. There's much more mobility and access to things outside of the house, which I'd argue significantly enriches childhood experience and leads to more adaptable adults.
As an adult, I'm overjoyed by the ease with which I can get to things around my city. I never have to deal with traffic, I can walk to three different grocery stores in under fifteen minutes. I have dozens of restaurants in similar distance, and I never worry about having too much to drink to safely drive home. I don't have to deal with traffic, and when friends come to visit (or when I visit them) I can take the train and enjoy a book instead of navigating roads. I feel far healthier and happier with the amount of light physical activity that's been baked into my life just by going about my normal routine. Before we moved to the city, I lived a pretty typical office worker sedentary life: I'd get up, shower, drive (sitting) to work, work (sitting, sometimes standing), then drive home. Now I walk to work and feel invigorated as I come through the door 15 minutes after I left, without the annoyance of rush hour or traffic or bad drivers. (A co-worker of mine lives out in the suburbs of our city, which are denser than most, and takes the light rail into work; half an hour on the train, 5 minute walk from the station. If he took a car, we'd need parking for him and everyone else that had one, and roads for it [see again, induced demand in my post above], and I wouldn't be able to walk to work myself). A twenty minute walk puts me at museums or bars or train stations or work or the store or like 5 friends' houses or the lake shore or a thousand other places. No parking, no navigating traffic, no having to move the car or worry about not wandering far from the car or figuring out how to navigate unfamiliar roads. Honestly the most stressful part of any of my journeys is wondering if drivers are paying attention as I go through the crosswalk, or if they're going to cut the corner to try to make their left turn.
As a citizen, my city's limited resources don't have to go to maintaining roads that the richer segments of the population get proportionally more benefit from. We can invest in more public services since we're not committed endlessly to maintaining the cost-sink of asphalt plains. [1] Public transit is an amazing economic equalizer as well: In a suburban environment, you must have a reliable car to make it to work. If you're too poor (or just starting out) to afford a car, or if it's unreliable, that's going to severely curtail your available job pool. (There's a common saying that "we don't all have the same time" when it comes to discussing class differences; my highschool girlfriend spent two hours on the bus, one way, to work, because her family only had one car, and her mother needed it for her job. That's four hours a day she can't use to cook, or study [she could try, but a bus is far from an ideal study environment], or sleep. If our town had better transit, or if our town wasn't so dense that it took two hours to travel from house to shopping district, it'd be a very different story.)
This is to say nothing of the actual health impact of cars: accidents, death, pollution, or just the amount of money we're 'required' to spend on them so we can participate in wider society. I feel like putting these at the end really undercuts their significance, but we never seem to talk about these facts. Car accidents are the eighth-leading cause of death in the US [2]. Imagine the economic savings, and the amount of medical resources, we could free up by reducing that. Imagine the value our citizens would get out of not paying $20k (at the _very low end_) every five or eight years for their cars, not to mention the maintenance.
[1]: https://www.youtube.com/watch?v=SfsCniN7Nsc [2]: https://www.cdc.gov/injury/features/global-road-safety/index...