These are the reasons why I love 21.9 over 16.9:
- majority of movies fill the entire screen up, no black bars at the top and bottom, any films that are shot in 16.9 will just have black bars at the sides instead. There is only one type of film that is problematic for 21.9 screens and that is the imax as they switch from 21.9 to 16.9 throughout the film i.e. Nolan's films, you can get non imax versions for most films if you really want though and even when zoomed in, it isn't too bad tbh, quality is still great and most of the time, you wouldn't even notice that the film is zoomed in
Here is a quick size comparison for a 21.9 film.
23" 16.9
29" 21.9
- You get more FOV at the sides in games:
http://imgur.com/a/docX3
minecraft, 16.9 VS 21.9:
http://cdn.overclock.net/b/b3/b33e8221_o3Inygx.png
http://cdn.overclock.net/e/e8/e84265e9_D0QRMwV.jpeg
Thankfully most of the games I have, support 21.9, the few that don't can be fixed by manually tweaking config files or using flawless widescreen. The only issue left is generally cut scenes/menus are 16.9 or/and the blood/rain effects will only show on the 16.9 area of your 21.9 screen i.e. you won't get effects on the right and left side of the screen
Overall 21.9 just feels a lot more immersive when it comes to media consumption, I like this article on why 21.9 is more important than 4k screens
http://www.pcgamer.com/lgs-34-inch-219-monitor-has-convinced-me-that-ultrawide-is-better-than-4k/
And lastly 34" 21.9 VS 27" 16.9 screen
As for curve, it isn't "needed", however, it makes 34" 21.9 better and easier on the eyes and supposedly even more immersive, curve is crap for TV's but for 34"+ monitors, it is a good thing afaic.