What an interesting question.
While we have public busses here in Pensacola, Florida, they do not run often enough or have enough routes to make them a viable means of transportation for most people. Therefore one can walk or take a taxi or drive himself therefore a car is almost a necessity, except in the largest cities, where we have efficient mass transit.
But the most important advantage of owning a car is that I do not have to ask my wife to let me use her car if it is raining and I do not want to get wet while riding my Harley.
The biggest disadvantage is the total cost of owning and operating any motorized vehicle which includes: purchase price, insurance, gasoline, maintenance, parking, toll roads and last but not least #@%*!?$& TAXES . Here the average cost to operate a cheap compact car is about US $0.75 per mile or about R$0.83 per KM.