The particles in the thermoplastic of Black Worbla are much finer than the sawdust in “classic” Worbla. This means it needs far less finishing than any of the other thermoplastics (with the exception of Thibra) to achieve a very smooth surface.
PROS: Needs the least amount of sanding and finishing. Handles curves really well just like regular Worbla.
CONS: Less sticky than regular Worbla, so needs to be heated longer/to a higher temperature in order to get it to adhere to itself, foam, or other thermoplastics. Best if you already have experience using regular Worbla.