As a kid, I always wanted to see what was going on in Spock's hooded viewer. But the whole reason for having a hooded viewer was to spare the need for data graphics, which were a heavier lift in the Sixties.
Then came TAS, and I think there was a time or two when they had an insert shot for Spock's viewer. And that's when you realize there is nothing that viewer could show that couldn't be displayed on an open monitor. [I hope someone recalls a specific example so I can see it at TrekCore.]
The only real-world justification for the hood would be if it's an instrument only one person at a time can see, in the manner of a periscope, but in Star Trek's case, more like a dim 3D hologram that has to be shaded from ambient light. For in-universe plausibility, that's our last hope.