It is certainly useful to get a diploma by passing all the exam subjects, but it is useless to pass the exam.

Self-taught examination is a part-time diploma, slightly worse than ordinary colleges and universities.

There must be a teacher to guide the students who take the self-taught exam.

Even if you go to Peking University, no one can guarantee you employment. Employment depends on oneself, and going to school is going to school, which are two different things.