My son sent me home with loads of the above to try out. Now I already knew it to be very good for model buildings, but am not sure that many others do.
I have embossed it with a variety of tools into patterns of brick, setts, tooled and rough stone and carr stone or flint and it takes any amount of treatment in this way. It is stiff and self-supporting, glues well with contact adhesives without melting and takes paint well. Really, I can't think of any downside.
This was done in Foamex:-
Anyone who fancies some for experimentation, please, let me know. I can get loads more.