Earlier quoted context omitted.
What are your definitions for "traditional Linux userspace software" and "traditional Linux users"? Do you consider Android to be "Linux"?
"Traditional Linux userspace software" is an informal definition, but let's say something like X. Or your average window manager. Or, say, almost anything from GNOME. "Traditional Linux users" is another informal definition, but if you use a distro, you're probably a traditional Linux user. Contrast this with an Android user. They run the Linux kernel but the software they interface with is an entirely different bree…
Considering there is already Steam for Linux, its probable that Valve will ensure Linux games run on both platforms equally well.
In any case, if there is no need for "all the trimmings", if Valve just wants to make an entertainment pipeline, then that's fine by me. It's the same kernel; this is a huge win for Linux by any measure.