This policy setting sets the "Zoom on roll with IntelliMouse'" option found under File tab | Options | Advanced | Editing ...

This policy setting sets the "Zoom on roll with IntelliMouse'" option found under File tab | Options | Advanced | Editing options

If you enable this policy setting, rolling the mouse wheel will change the zoom level of the worksheet.

If you disable or do not configure this policy setting, rolling the mouse wheel will scroll the worksheet. This is the default behavior.