It does actually mention heater cables in one of the amano books, i remember reading that quote to. I have heard that they are beneficial, but don't know of any real comparisons to prove that. I guess the theory is that in the tropics the sun penetrates to the bottom of the water then the heat sort of rises. But if that were true, you would imagine that it would be more of a light penetrating effect as opposed to a heat source. Heat tape is very concentrated. Anyone who keeps reptiles will know that its a very centralized way of heating something, that would make it impractical for under an aquarium. A heat pad may be better but they are hard to control. There is a heat rope product that looks like a bead of tooth paste ( the only way i can describe it). It doesn't have the same problems as the tape, its easier to work with, yet not as hot. If you wanted to try this it might be your best bet. I guess its one of those things, i don't think its necessary either. But with that said, perhaps you will discover some missing element....if you want it, try it, prove everyone wrong. Ive always wondered myself if its beneficial, but there is no studies ive seen the actually conclude to that. If anyone knows of any, please share.