Difference between Vacancies created from My Teams and My Client Groups

Summary: Hi All, I wanted to understand , when the LM creates a vacancy from My Teams > Actions , I understand its a placeholder , like holding a headcount for a temporary period of time, but When a HR Specialist creates a vacancy under Home>Employment>Vacancies, they have to select an employee under who they are creating the vacancy. What would be the difference ? I am getting confused between these places of creating vacancies.

Content (required): Now in a world where are using ORC for our requirement and positions as our workforce structure to create requisitions, I don't think there is a need for vacancy. Kindly correct me If I am wrong here.