I frankly don't understand the point of such monitors. If they are placed reasonably near, they don't fit human FOV well, and the periphery is seen distorted. If they are far enough away, the pixel pitch goes well past the angular resolution of the eye.
Let's say I have an ide open, I will likely not look at the directory structure often, but I want an easy way to switch files - fantastic for having it available just by glancing over
Now you run tests, start the application etc. It also doesn't need to be in your view, all the time - but isn't it convenient to be able to just look where you know it's?
It's suboptimal for competitive gaming however, exactly for the reason you said. Scenic gaming on the other hand is improved by it, because the larger screen is more innersive
There is a way of using Stage Manager as though it was Spaces, with minimal animations, but it takes a lot of getting used to and it's still not great.
Scenic gaming seems pretty niche outside of dedicated flight/driving sim setups? And regular gaming often kind of sucks on ultrawides - way too few games have decent options to pull the HUD into the center region of the display
Same with monitors.
Either you stack huge piles of papers and work through the piles (with everything in the way all the time) or you spread them out in front of you.