From the WC article:
These screenshots are also an early look at what PCs will look like when CShell arrives, with the addition of Win32 support, of course. The idea with CShell here is to bring the exact same desktop environment to phones, and vice versa. So, it makes sense to see CShell Continuum mimicking the desktop because it is the desktop. It'll be the same desktop environment on PC as it is on phone devices.
I highlight this paragraph because it underlines again Microsoft vision for 'Windows 10 everywhere'. The OS (and now interface too) on the phone is the same on Continuum displays and on tablets and desktops. The same code, the same modules, etc.
Anyway, on with the video:
The significance of this even working at all is that we now know that Redstone 3 works on some Windows 10 Mobile devices. Having half resigned ourselves to 'feature2' being the branch that many devices will end their journey on, we now know that at least the Elite x3, with its Snapdragon 820 chipset, will run Redstone 3 and pretty well. No boot loops, no real issues, other than the beta-ish nature of RS3 at the moment.
By extension, I'd expect the Alcatel IDOL 4S Pro to also run this branch of the OS when it's released. And by extension, I'd also expect that these two phones will be opened up into the Insider programme for Redstone 3 (on the Fast ring) at some point - after all, there must be some other Elite x3s inside Microsoft being used as mobile test beds. And, when the time is right, maybe these phones will get Redstone 3 ('The Fall Creators Update') officially too?
What of the Lumia 950 family, running Snapdragon 808 and 810 processors? My prediction is that these will still max out at 'feature2' builds, even via the Fast ring, but I'd be delighted to be proved wrong. Perhaps, at some point over the summer, 'feature2' builds will magically give way to 'RS3' builds and then the fun can start in earnest for far more phones than just the x3 and IDOL.