I think I’d be a good person to answer this. I’ve lived in Houston (needless to say, extremely car-friendly) without a car for almost 2 years; currently I’m living in a city that banned cars within its city center in 2015, but the rest of the country is still very pro-car and quite car-friendly

A couple of things that cars benefit everyday life that would be difficult to do without a car. There’s probably more but these are the ones I can think of:

• Accessibility to places that have difficulty justifying being served by public transit. These include poorer neighborhoods that are far away from city center, semi-rural natural preserves, extreme geographical difficulties, … Case in point, Houston has a lot of nature/green spaces that were 20-30 miles outside of the city center… good luck getting to these without a car (trust me, I tried once)
• For certain physically disabled people, driving would be easier than walking/biking/public transit… Especially in particularly hilly cities, centuries-old cities where roads were paved no better than playgrounds, or sometimes both. This can be somewhat mitigated with good infrastructure projects, but cars are usually an easier solution
• Car-free zones can get very crowded, very fast. This is usually a good thing in terms of urbanism… but some find it uncomfortable for various reasons. My current city is actually a rather extreme example: they are now considering banning bikes in the city center too, due to pedestrian injuries
• I know cars are prone to needing repair, but with how the road network functions, personal vehicles can reduce a lot of dependencies on external factors such as public transit being functional. Case in point, two months ago NL’s national rail company became essentially non-operational due to extreme weather, which would be rather devastating if your only way of commuting to work relies on the train

Also I think these two positive points associated with cars are actually quite doable without cars:

• Hauling stuff from point A to point B: delivery companies and car-rentals exist for a reason! This is surprisingly doable even without owning a car (you are technically using someone else’s car in this case). Of course doing it without your own car will be more expensive… but we do have the logistics for it, especially if the entire society shifts to a car-free model
• Not all rural areas need cars: some are actually quite doable by walking alone due to how small they are (I have a friend who lives in a rural American town like that: yes everyone drives, but everything is also 30-minutes on foot if you don’t mind walking). And there are quite a few parts of the world where rural towns are served by trains frequently
• Road trips: scenic railways exist for a reason… and unlike point 1 I made, sightseeing trains actually do make money, so there is pretty good justification for building them