After graduating from college, most people will go to work. If you are a language major, you will probably use CET-4 and CET-6 when looking for a job. If other majors are not so demanding of English, actually CET-4 and CET-6 will not have much effect. Of course, if the work unit really needs it, you can ask if you can use other English level certificates instead. For example, CET-4 or TOEFL IELTS, as shown below.
If you want to go abroad or something, my suggestion is to take TOEFL and IELTS English.
There is another kind of students who will choose to go to graduate school. These students don't have to worry. They can also take CET-4 and CET-6 during their graduate studies. During the re-examination during the postgraduate entrance examination, if you can take one more CET-4 and CET-6, you will have certain advantages over other students, so if you can pass CET-4 and CET-6 in college, try to live in college.