As everyone else has said, there are lots of reasons based on personal finances, personal circumstances, and preferences.
DH and I know nothing about cars. So we are never going to buy a cheap second hand car because quite frankly, we wouldn't be able to tell the difference between a car that will work well and one that is going to need lots of expensive repairs.
Which means we always have to finance becuase we can't afford a newer/more reliably reliable car outright.
But then, becuase we are the people we are, we get loands and pay off those cars. So we have two cars. One we bought new on a 0% finance deal and, at the end of the deal, we refinanced the remaining amount and we paid that off. That car is now, on paper, worth very little but it's been a fantastic purchase for us and we've been driving it for 10 years, it's reliable, cheap to run, very few repairs and is a very comfortable, large family car.
My car we financed but will be paid off shortly. We paid £14000 for it and had a large deposit from our previous car. Financing was over 4 years and now it's ours, and worth about £9k. Ideally, we'll drive it for another 3-5 years at least, but there are a few issues with it so we might not. We haven't decided yet.
Meanwhile, my sister prefers to pay a flat amount o fmoney every month for years, knmowing that she always gets a new car every 3 years that is reliable, fun to drive, comfortable, big enough etc etc etc. She just sees it as a cost she has to pay every month and that's fine - it's cheaper than buying the car or financing it on a loan.