Section access is used for:
1. Authorize user to open QV application. This is required.
2. Restrict user access to the data. This functionality is optional.
There is no "sheet level" nor "object level" section access. But you can use it for this purpose by utilizing function QVUser(). For example, you want a sheet or object to be visible only for users A, B, and C. In this case, enter this in Show condition:
I must add that you don't need section access for this purpose. The same can be done by using function OSUser().