It's not because a system leaks energy that it necessarily loses its value completely. When I use a light bulb, I need electricity and heat is generated. But th

It's not because a system leaks energy that it necessarily loses its value completely. When I use a light bulb, I need electricity and heat is generated. But the light is providing what it's used for. The loss of energy is not important enough to jeopardize the system - it still successfully accomplishes its goal within the set parameters.