'S' is for "special"... as in, "Isn't that speeecial..."
From the second link:
Performance - The Big Selling Point
Microsoft has yet to reveal what Windows 10 S stands for, but ‘Speed’ would be as good a choice as any. Windows 10 S will boot in just 15 seconds. It is built on the same core as Windows 10 but is more lightweight, running on lesser hardware configurations which allows for both the purchase of very cheap PCs (more later) but also installation on older hardware to bring it back to life.
If you’re setting up multiple computers, Windows 10 S can also be installed via USB with preconfigured options. That’s a big time saver.
So they're just now catching up to what Linux has been able to do for years...
The Bad News
Goodbye Desktop Programs
Yes, just like Microsoft’s failed Windows RT platform, Windows 10 S will not run software you have to install from the desktop. Currently that means no Chrome, no Firefox, no iTunes, numerous games and much much more.
Microsoft Windows 10S cannot run any programs which must be installed from the desktop
Instead all Windows 10 S software comes from the Windows Store. Microsoft rightly points out this should mean software is safer, a big deal for schools and businesses, but currently the Windows Store is a wasteland. Will the likes of Google and Apple repackage their software so it can be installed on Windows 10 S via the Windows Store? That seems a big ask.
Meanwhile, back in Linuxland...
While Linux may
prefer that you install programs from your distribution's official repositories (and there are a whole lot of programs available through those), you still have other options for direct installation. Flexibility, thy name is Linux.
Granted, there are certain programs which won't run on Linux, and if you happen to need one of those, you're stuck with Windows. But for the majority of people who write very few documents, and mostly just browse the internet, listen to music, watch Netflix, and check their emails, there is no need to give all your private information to MS, and be shackled by their many consumer-
unfriendly practices...