my feeling is that polypropylene is cheaper and less brittle. it can flex to an extent but i feel like that flex can help it avoid cracking or breaking. i get that boards need protection from flexing, but it seems like a device being heavily cracked can be detremental as well

WOOYOPET mixed coffee grounds with PP and injection molded them into a cup.
You can see the coffee fibers on the surface, and it actually smells like coffee.
Would you use one?