General Tile Discussion

I understand the reasoning not to use 2x4's for Shower Curbs. I see the options for Schluter Foam Curbs and I noted that Isaac builds his own curbs using layers of 2" Kerdi Foam Board. Has anyone considered using other material such as several layers of Composite Deck Board? Can anyone think of a reason that would not work? I do see that it is fairly expensive.

Thanks in advance.