Honestly, what other reason do you have to need such a private screen?
I remember there was a movie some years back called “Brainstorm” where the great advance was that they found a way to record people’s experiences and play them back to people wo others could actually experience them inside their brains.
The first “victim” of the technology was some guy working for the company who got his hands on the first sex recorded that way, and figured out how to splice the thing into a loop...
When they found him the next morning still wearing the device running the playback in a loop, he was a quivering mass of protoplasm, and his brain was fried!
“Honestly, what other reason do you have to need such a private screen?”
It is more than just a private screen. VR users often get engrossed in the interactive environment and become oblivious that their movements are being observed by others.
I can think of a number of medical and technical uses, but innovation will still probably be funded by the porn industry.