Steam OS is an unethical OS that is basically a pirate OS. Valve would not have reached its scale if not for Microsoft and Windows. And instead of thanking MS, they stole the APIs that MS invested in creating and getting developers to use. Yes, this is legal, because a quirk in the law prohibits copyrighting the API or patenting software, but that doesn't make it ethical.
This site has done a good job criticizing AI for learning by using written and artistic work of others, whom it might subsequently displace after learning from their hard, creative work. That's exactly what Steam OS is to Windows and it's unethical. That alone is enough of a reason for me, and hopefully others, to never use Steam OS.
How is Steam OS a threat to Windows? Not today, but in the long run, it weakens one of the chief marketing arguments for using Windows vs. Mac OS or other competing computer OS. This is because one of Windows competitive advantages against Mac OS is that in addition to running all the productivity software, Windows is ALSO the only OS that really supports gaming (similar reason Android beat Windows Phone OS on mobile -- if you wanted access to all apps, including games, Android was the only choice). If gamers leave Windows for Steam OS, then their computer device might as well be a Mac instead of a Windows PC.
None of this means that Steam OS provides a bad UX or that Windows provides a good UX. There's plenty of legit reason to criticize Microsoft for its gaming work and to applaud Valve's contributions to gaming with Steam on Windows and the hardware design of the Steam Deck. But that doesn't mean a Microsoft-focused site called WINDOWS Central should ever cover Steam OS without at least acknowledging that it's a threat to Windows. Valve's CEO has said himself that he hopes to knock down Windows.
Note that this is nothing like PlayStation vs. Xbox. Sony did its own work to build PS, as MS did to build Xbox. Those are legit competitors, slugging it out fairly. Same with Mac OS in the OS realm. Steam OS is completely different, stealing from MS like a pirate OS, and is not a legit player in the market.