Good call wienkeg.
That foam, sand-less grout, non-toxic paint and non-toxic sealer can be used to create custom hides or terrarium architecture. Just not in the manner he chose.
There are a ton of video's on youtube on how to do this.
Since you like the look, learn from the very similar things others have been working with and correcting our own mistakes with for some time.
For BP's I would avoid the "stick eco-earth on the foam" ones. Those you would be throwing out too often because they can't be cleaned properly.