While having breakfast today I laid down my iPhone 11 Pro (appx. same height as the Duo) perpendicular to my viewing direction and and imagined it being around 50% wider and having a second screen rising up from the back edge like the screen of a laptop.
The Duo might be the perfect device for that situation, just casually catching up on news, messages etc. at the breakfast table. Like a mini laptop where the bottom half becomes a notepad, music app, WhatsApp window, second browser screen or whatever, while you continue your overview on the top display uninterrupted. A normal phone propped up sideways would obviously be too narrow, but the extra width of each Duo screen probably gives you enough display height in that situation.
Sorry for starting to sound like a Microsoft shill at this point But I'm just getting really hot for this device and can't stop playing around with imagining what it would be like to use in real world situations. The real hands-ons and reviews can't come soon enough!