Why investment and financial management are not allowed to distribute leaflets?

Maybe I think it is not standardized to distribute leaflets, and my credibility is reduced. But not necessarily, some formal companies sometimes send out some brochures for publicity. I received the brochure of Qingdao Zhong Rui Yuan Bo, and I also scanned their WeChat, so I went to have a look nearby. It depends on the company. . . I hope my answer can help you.