It's for reentry. Normal satellite create alumina particles.

All the satellites which re-enter the Earth’s atmosphere burn and create tiny alumina particles, which will float in the upper atmosphere for many years,” Takao Doi, a Japanese astronaut and aerospace engineer with Kyoto University, warned recently. “Eventually, it will affect the environment of the Earth.

Satellites all eventually come back down though. I think they're hoping for satellites that when they come down and burn up, less expensive and wasteful materials are lost.

I’m kind of baffled you wouldn’t read the Article and instead jump to conclusions and assume that some of the smartest people on the Planet would overlook such a huge flaw.

I suppose it's got a lower carbon emission than steel or aluminum even after you account for it burning up on de-orbit, considering the fuel cost for metal refining.