First, let me clearly state that I am no expert of holsters. I have (shamefully) tended to stick to cheaper holsters (Hello, Uncle Mike's), and of quality holsters, I've tended toward the cheap end. However, I understand VERY well the concept of a holster. The accepted definition is fairly simple and straightforward: a sheathlike carrying case for a firearm, attached to a belt, shoulder sling, or saddle. I would modify that definition by making this simple change: a sheathlike device used for SAFELY carrying a firearm....
The goal of carrying a sidearm is to do so safely. When one is armed, one must take reasonable precautions to verify that they are not taking foolish risks with their safety. It's not very difficult to imagine a circumstance in which an object (arm of a chair, wooden dowel rod, etc) can apply pressure inside the trigger guard when it is only covered by a layer or two of clothing.
I also have serious issues with inserting anything which doesn't belong into the end of the barrel. It sounds like they attempted to make it a material which will do no damage, and it certainly sounds more delicate than the cleaning brushes I tend to use. However, that is only done as needed, and only for a short time. The motions which my body performs on a daily basis (walking, sitting, standing, laying, driving, breathing) will all cause motion in the pants. This means more friction, more rubbing, and a greater possibility that it will cause damage.
Overall, while this is a very interesting concept, and I am definitely a minimalist when it comes to holsters, I do not think this is a good idea as is. There are a couple variations which might make me more comfortable with it, however as it stands, I'd not want to carry my sidearm with it.