The Zhejiang Association is a completely volunteer-based organization with no funding source. Other cities and prefectures are organized directly by the local industrial and commercial bureau, typically once a year. Zhejiang has delegated this responsibility to the association, resulting in more frequent meetings.
However, organizing exams requires funding for personnel, venue rental, exam papers, travel expenses, and administrative costs. As a club-like association, prioritizing membership slots is understandable. Charging a 50 yuan fee for physical card production for non-members is also acceptable. Of course, those who don't want to join or pay, can choose the "electronic card" option.
In conclusion, I don't see any problems with this operation.
P.S.: My B-level driving test was in Zhejiang, and at that time I didn't choose a specific location. The cost was 200 yuan per exam.