I was being facetious. I'd be willing to bet it's because most people would think 16:9 is bigger otherwise. http://mentalfloss.com/article/76144/why-no-one-wanted-aws-third-pound-burger
21:9 is easier to compare, that's most probably why they chose it as a spec. There is a super ultrawide format as well 32:9 (double 16:9 obviously). http://www.guru3d.com/news-story/samsung-launches-chg-90-dr-compatible-49-inch-curved-ultra-wide-monitor.html
I've only come across a handful of games which didn't offer at least basic widescreen support, and almost all of those were small indie titles. The most disappointing is Overwatch, with its locked max FoV, it means 21:9 players get the top/bottom docked off. :( 16:9 vs 21:9
I think a 21:9 Monitor can be useful. Todays UI is often at the left and/or right side so a 21:9 Monitor can help to archive a more natural 16:9 viewport. For single content creation its maybe not important but for a Leveldesigner its a pain in the ass to have a small vieport or you must alyways change into ingame mode for…
Do not buy 1080p ultrawide monitor because they're (2560*1080) just a standard 1440p monitor with bottom part cropped. You'll be better off with a single 16:9 1440p monitor than that. Dual 1080p may have some advantages then single 1440p and so on. If you can afford it buy any monitor with 1440 pixel vertical resolution…
I just answered this question over in the PC building thread, so I'll just copy/paste what I wrote there: Ultrawide / 21:9 displays: For content creation, the main issue is limited options available at 3440x1440 right now (1440p ultrawide), and they don't give you as much screen space as a dual monitor setup would. There…