When Blizzard rolled out 21:9 screen support to Overwatch's Public Test Region today, people lucky enough to own a monitor that wide were pretty chuffed. For a while, Blizzard had ruled it out, stating last year that it might lead to a situation of "Haves and Have-nots", where folk with a wider field of view might hold a competitive advantage over people using 16:9 monitors.
That policy still remains intact however, because according to users on Battle.net, the 21:9 setting doesn't actually widen the field of view, but rather narrows it. Basically, if you compare these images taken by user Fin on the forums, you'll notice that the wider, 21:9 version is the same as the 16:9 version, only cropped at the top and bottom.
Here's the 21:9 version:
...and here's the 16:9 version:
After a long thread on Battle.net, game director Jeff Kaplan eventually weighed in, confirming the studio's stance on FOV and competitive advantages. "We do not plan to increase the max FOV beyond 103, in any resolution," he wrote.
"As a result, this doesn't leave us with a lot of options for 21:9 support. I know this is not the answer our 21:9 players want to hear. But we feel like it would be unfair to 16:10 and 16:9 players if 21:9 gave a substantial FOV advantage."
So there you have it: 21:9 support is technically there, but you'll want to weather the (perhaps minor) disadvantages if you intend to use it.