When would they have demonstrated this tech?
Anyway, the Feds have the same tech: B'Elanna Torres was at one point able to install holoemitters around the Voyager so that most of its interior became a holodeck. A smaller-scale version was used onboard the Defiant in "For the Uniform", but never caught on. It was more an obstruction than an asset: why let your communications partner hog the floor when you can confine him or her to the wall, out of the way?
In any case, UFP viewscreens appear to be holographic: if viewed from the starboard side, they reveal the left cheek of the person in the screen, if from port, then the right cheek. (That's because the visual effect is easier to film that way.)
Timo Saloniemi