This is where I will agree to disagree. I can't say for snakes, because it really doesn't seem to matter (although i keep mine in a deep dirt substrate) but for lizards, (more so monitors and tegus) but I believe for all lizards, have a substrait that can safely retain moisture (even very little in the case of a beardie) without becomming satuarated, providing them the ability to burrow and have a moist hide DOES in fact prevent things such a gout and dehydration. Which can slowly over YEARS kill a lizard.