The point of a collimated screen is to present an accurate representation of the outside world from any viewpoint within the sim.
Computer screens or projectors work absolutely fine, but they will display a biased picture depending on the setup. If you have ever used these types you will have witnessed the sim instructor switching the viewpoints depending if you're in the left or right hand seat.
Not sure if a continuous wrap around style LCD or LED screen would be the same but I would imagine so.