I like my family well enough, but it seems very constraining to me to be forced into the same career choice. Plus any tensions at home are hard to get away from; there's no alone time. It's also financially risky because if the business goes under, everyone in the family will suffer.
I am sure there are various reasons to participate in a family business, such as enjoying the work and wanting a sense of continuity. Or it may be a case of limited financial resources in the family, which go further if shared in a joint venture. Dealing with discrimination and limited opportunities can be another reason to stay in the family business. All of these reasons seem valid to me. I have to admit even I find it impressive when you read about businesses in Japan that have been in continual operation for over 1000 years, run by the same family.
But I have also seen plenty of cases where a useless and untalented member of the family is given a position, to the detriment of the business. For that person, I'm sure it is easier to step into a role than make a place in the world, and to get away with laziness and incompetence that would get you fired anywhere else. And of course the person doing the hiring is usually the breeder, trying to protect their spawn from the consequences of being useless.