I think it's way more common than in Italy. Here we finish high school one year older, and also we don't need any volunteering/work experience or similar requirements for any of our degrees, so if anyone takes a gap year is more for the experience, or if not sure about what to study at uni. Also uni application process it's easier and way later in the year, giving you more time to think.
Lastly, at least in Italy, you can't retake your final exam, so you just have to keep the grade you got.
These are some of the reasons I can think about!