I'd expect the loss coefficient (tan d) to be terrible. Cellulosics hold onto water quite well. You will not have a good time pushing anything high-speed through this kind of board.

I would say the only practical application would be disposable things like PCBs in single-use vape pens. (Which are pretty environmentally offensive on other levels anyway.)

> Not one mention of the material's dialectric constant

They weren't able to measure it because it kept changing. /s