Some people think car camping is sleeping in a car. In reality car camping is using a car to get to a campsite, the opposite of backpacking. You can sleep in a car at a campsite but you still have to find a place to put your gear while you sleep. This includes food.
While most campsites are easy to get to, there are some that are remote and off the beaten path. I found such a place in the Berkshire Mountains but I'm not going to disclose it's location. It takes hours of highway driving to get to the area and I do not like to drive that long to find my favorite spot over run, but that is not the important part.
If you are going that far into the woods you need a dependable set of wheels. The campsite is 24 miles down a dirt road with very little to no traffic. You can walk out if you had to but it will take a few days. How long does it take you to walk 24 miles?
I was hunting in Maine years ago in quad T7 R8 Wels when my 85 Chevy pickup quit on me. I discovered the floats in the carburetor were stuck so I took the carburetor apart. The guys with me said I was crazy. I answered " Well, it's either fix it here or start walking". We drove out.
When car camping you can bring more gear with you than backpacking but basically the same cautions, rules and courtesies apply. See our pages on Camp Safety, Camping with Bears and Where to Set Up a Tent.
There are thousands of families sleeping in their cars. It is not because they think that is car camping it is because they have no choice. With the economy the way it is they have lost their job, and home and have no other place to sleep. They are homeless.
When someone says they were car camping for a while, they may mean they were living out of their car because of bad times.