These pointers are generally provided by the ActiveX control and then used as parameters to call methods of secondary interfaces.
One notable exception concerns IDispatch interface pointers, which can be used to set the font or image (cursor, bitmap, icon, etc.) for a particular part of an ActiveX control.
You can create this type of pointer using the VaToolBx DLL's VaToolBxCreateFont and VaToolBxCreatePicture functions.