For automation purposes.
I have an ender-thermic pump hooked up to a magmatic engine and ender tank feeding my smeltery with lava, however if I leave the magmatic engine just running it wastes lava, and I don't want to do that so I want to know if the ender tank is full I want to stop the engine if the tank is full, and I kinda don't want to go to the Nether every 5 minutes to see if the tank is full because I'm a little bit lazy.