Ken , it’s just that most people don’t realize what happens when you skin Foam with a nice fabric .... It gets very Solid ... and as the extruded foam compresses it exponentially offers more and more resistance to puncture... Beaded foam does not do that and limbs , etc, pass right through the soft stuff ...
Here’s a pic of a fairly large rotten limb that punctured 10 holes in the roof of my Commercial trailer , the roof was 1.5” beaded foam with a 3/32” soft plywood (cheap luan) and a literally paper thin vinyl “membrane” skin

... Several parts of the limb penetrated the roof completely and were found on the floor inside ...

Glad I wasn’t inside ...
