That picture linked above by Seeteeyou is mine, cool mini yay
Atmos isn't always upmixed. There is content out there, just not a lot of it:
Battlefield 1
Battlefront
Movies - Select few, and even fewer that you might want to actually watch.
Dolby Access App Demos
Dolby Atmos Test Tones.
(Actually, I haven't come acrossed content that is upmixed. When I listen to non Atmos content, nothing comes out of my height speakers. I'm not saying it doesn't exist, I just haven't come acrossed it.)
If you watch Ninja Turtles through the built in "Movies and Tv" in windows, you can actually select the Atmos audio track. That's the only Atmos movie I have so far, I'm hoping to get Hancock.
As far as Overwatch goes, it's only through the built in setting. Those with receivers are out of luck. Zero Height sound. Dolby Atmos for Headphones = same boat. It's only by the built in setting.
Dolby Access App has a ton of issues for everyone. It always seems to be temporarily remedied for some random amount of time by: Uninstall, restart, reinstall. For all the content I've found, the Dolby Atmos for headphones (Windows setting) doesn't work in any Atmos content I have found. You cannot enable it in Battlefield 1/Battlefront and you cannot watch movies with it. I did read somewhere that using an old game like Diablo3 (Where you can select 5.1/7.1 through the audio setup) created quite a noticeable difference, but that same user also stated he noticed no difference in newer titles.
Since the Dolby Access App came out to the public on April 5/6 (Whichever). It's been updated many times for better or worse. Let's hope that they keep working on it. As far as my receiver, goes, I can fidget to get the spatial sound setting to work, but I'm not sure what I'm actually getting. I can still play games and watch movies in Atmos with it off. So for now I leave it off. (Well it turns itself off, I just gave up turning it back on).
Don't bang your head too hard trying to get this thing to work.