The "worthless" thing that's being protected is human life. The idea of sending exotic signals with dramatic structures was just a brainstorming exercise that

The "worthless" thing that's being protected is human life. The idea of sending exotic signals with dramatic structures was just a brainstorming exercise that gets a lot of publicity because it seems exciting. But there's a definite risk that the waste would attract rather than repel innocent discoverers: See https://en.wikipedia.org/wiki/Goiânia_accident https://en.wikipedia.org/wiki/Goiânia_accident