Where I live, home schooling is a great idea. Most government schools allow home schooled students to take 1 class a year for free in the government schools. So if a parent doesn't know trig or some other advanced subject and the student isn't able to teach himself, it isn't a problem. He can go to the government school, pay for a tutor, pay for an online class or take 1 of the many free online classes. The same is true if the parents have to travel around a lot. If the parents is a diplomat, actor, musician or something like that.
Benefits of home schooling? It allows students to work while going to school. For example, if the child is in a band or a child actor, it is very hard to go to school during the day with all of the traveling and filming. Being home schooled allows a child to finish school 2-4 years earlier or take classes around their busy schedule.
Home schooling is also great for people that are zoned to go to poor performing or dangerous government schools. It only costs a a few hundred dollars a year and some areas offer scholarships that cover all costs. It's really good for families if they want their children to compete in national competitions such as spelling, geographic, science or beauty competitions. During a typical day, 2-4 hours of time is wasted by government schools. Students can use this time to study the subject they are competing in.
Some people live in very rural areas that don't offer government schools. They usually have 1-3 choices. School by mail, online schooling or home school. For these students, home schooling is usually the easiest and least expensive option.