I have used it
Here are the cons of that material;
Not really kydex so it does have some different properties.
It will crack over time, stress fractures really, and they show.
I will not make Taco style sheaths out of it as they are guaranteed to crack. Only pancake style on clear.
Hard to work with = cost more. not only does the material cost more but because it is quite a bit harder to work with I will charge more.
If you ever get anything, I do mean anything, lint dust wood bits and so on, they are in there forever and if you are slightly OCD it will get to you.
As you take the knife in and out of the sheath the wear will show up as light opaque marks and will bother you.
Pros;
It is a novel idea and can look neat.
I have made a few and have some of the material left if you are determined that is what you need.