From Lockheed-Martin themselves, which doesn't require you to register; https://lockheedmartin.com/content/dam/ ... orange.pdf
While essentially the same, I believe the purpose for F1 cars are more to push airflow around the side instead of over the top. And the wing or VGs are just different ways to achieve this goal. Most cars use a wing element over the sidepod, but those that still utilize the vertical elements all have them located at the outside portion, where the sidepod takes a steep downward curve to merge into the side. I believe it is only McLAren that uses these VGs. The rest that use the vertical elements have them connected to the wing element.
I believe the point in F1 is to 'push' air outwards down the side of the sidepod, utilizing the vortices(or wing element) to keep the flow attached in this quick vertical turn.