The "superficial" difference is that a public service instructor cannot charge the public, while a professional instructor can charge the public.
The deeper difference is that the state's requirements for public service social sports instructors in terms of their own sports skills and instructing ability are not high, and it is not difficult to obtain a public service social sports instructor certificate (note that public service social sports instructors only have social sports instructor certificates, not a national vocational qualification certificate, and that social sports instructor certificates are free of charge from the state for training and assessment and issuance. The gold content of the certificate is far less than the vocational certificate of the state), and at the same time stipulates that the public welfare social sports instructors are not allowed to carry out paid services of a fee nature.
Referring to the professional social sports instructors, the state has strict requirements for this kind of people both in terms of their own skills and instructing ability, and stipulates that they must pay the training fee, appraisal fee, participate in vocational training and pass the examination, and obtain the national vocational qualification certificate (the difficulty of obtaining the certificate is much higher than the public welfare certificates, and the initiative to enroll in the program, pay the fee, and participate in the professional training may not be able to get through the examination) and qualified certification. After that, they are allowed to carry out professional services for a fee in the teaching of the corresponding sports programs.
That's why you won't be asked to pay a fee to learn square dancing with an older woman, and you'll have to pay a fee to the instructor to hire a personal trainer at the gym or to learn taekwondo.
Friends who are interested in vocational national vocational qualification certificate, you can go to follow the public number of Leqi Sports, that is a platform specializing in national vocational qualification training institutions, you can learn more about the relevant information needed to apply for the test from above.