This is very similar to a product I would occasionally use at work. I'm a retired dental technician and I would get impressions in the lab from one of my doctors who used this type of material for making custom impression trays chairside. It has been around for decades, I think it was called T.A.K. (or something like that).
This Blue Stuff appears to be a wee bit more flexible in it's cooled state. I never thought of using the tray material to make molds, I imagine it would have worked well if there weren't too many undercuts.
I know it would capture details nicely as it would always be covered with my fingerprints very prominently on its surface.
I would guess Blue Stuff is the same material reformulated to be more flexible...I'm going to try some of my old tray material for the hell of it. I'm definitely going to grab some Blue Stuff as well.