As far as high CR, for on/off CR without lights on the screen won't affect that. These screens could get some people to only watch with lights on, at which point the CR of the projector won't matter as much (although the screen will help retain what CR is there).
As far as high lumen, it depends on what the lumens were for. If they were to fight other light (lights on or light coming into the room) then a screen like this could reduce the need for high lumens. However, if the extra light was just for lighting up a really big screen, then this "black" feature itself shouldn't change that. Could actually make it go in the opposite direction for some of us who use the High Power, since this screen is lower gain (at least in the ideal viewing positions) and so going to this screen could mean we need more light output from the projector.
I wonder if it would be possible to get a small sample. I would even be willing to pay something for one, but could talk to a friend who does reviews and see if he could get a sample to look at. Or maybe they would send one to Tryg. I think this screen could work well in his setup.