I use a Sony 70" flatscreen TV for flight-sims (and other games where immersion in the game world is important). I sit about 2 metres away from the screen.
While you can get the same arc of view with a smaller screen placed closer to your eyes, I prefer this setup:
1) Because I need prescription glasses (myopia combining with long-sightedness as I age
): so with a large screen placed further away I do not need a special set of prescription lenses just for that viewing distance, but can use my regular infinity set. Not a problem for you youngsters....yet, he he.
2) Compared with a closer, smaller screen the illusion of immersion in the game world is more compelling. I am not sure why this is so, unless perhaps it is because your brain "knows" it is looking at something close to you with a smaller screen, simply because the eye is focused at a short viewing distance.