Another reason for raising the substrate is to provide room for a submersible heater. Heaters are not to contact anything but water therefore can only be used in a tank with a false bottom or a resevoir outside the tank. Some people use false bottom tanks to elevate plants out of the water and keep them from rotting. Most of the commonly used terrarium plants don't do well planted in soil that stays continuously wet. We set up a false bottom tank and documented it as we went along, to see what we did follow the link.
Naturalistic tanks provide some of their own food source.
Look closely and you will see small insects and such climbing about. A tastey treat for a hungry dart frog. Live plants help to breakdown pollutants in the tank such as nitrates. They also provide many hidding places which surprisingly persuede your frogs to hide less. They hide less because they are more comfortalbe knowing safety is only a speedy hop away.