I would think the underbody panels are more for overall (underall?) airflow ... laminar, less turbulent if you will.Every car I've owned since my 1999 VW Passat has had one.
They are often present as much to help channel airflow through the radiator as anything else.
Just remember that it's plastic and probably won't survive if you go rock crawling. Other than that, there's really nothing to consider.