Interesting idea, I never thought of that. But the threads I'm finding on this topic have mixed reviews of it working.
I also found a lot of people mentioning that it crumbles very easily if disturbed while wet. Another critical fact that isn't included on the substrate sticky... Was trying to lobby to see if anyone was interested in updating/beefing up the sticky but that didn't really go anywhere. Having the substrate break down easily, seems to me like a big con!