I understand! Coming from my perspective: my snake is normally housed in a 20G long, but since I'm going to be away for 2 weeks, he's in a tub b/c he's going to be watched by my friend who also has reptiles. Also running the space heater was getting a little pricey so I tinkered with the CHE and it's working well so far.
But I do understand the risks if the CHE isn't controlled. When I first got it I let it run and it was producing temps well over 300F.