If you take it off, what do you see? I imagine you'd see the edges of the fiberglass insulation between the floor and the belly skin. You really don't want to hit a puddle and splash a big load of water in there - it'll take forever to dry out, and rot your floor and rust the frame in the process...
I believe it also insulates the p-trap somewhat during those near-freezing nights when the trailer is still in use and not winterized by holding the interior heated air inside.
This website is not affiliated with or endorsed by the Airstream, Inc. or any of its affiliates. Airstream is a registered trademark of Airstream Inc. All rights reserved. Airstream trademark used under license to Social Knowledge LLC.