The Steam Deck's popularity has meant Linux is the second biggest OS for Steam

techradar.com:

Linux is now the second biggest operating system for Steam owing to the popularity of Valve's Steam Deck handheld PC, overtaking Mac OS. 

The Steam Deck's continued dominance in the PC gaming industry shows no signs of slowing down. As one of the best handheld game consoles, its popularity has meant that Linux is now the second most popular OS for Steam. A recent Steam Hardware & Software Survey has confirmed that Linux now accounts for 1.96% of Steam's user base (a 0.52% rise) as opposed to Mac OSX's 1.84%. According to Ars Technica, a total of 42% of the Linux figure can be accounted to SteamOS Holo, which powers the portable PC.

While the vast majority of Steam users are Windows-based, with a total of 96.21% across all versions of Microsoft's OS, this is the biggest development made with Linux's adoption yet. The climbing rate isn't surprising when considering that Steam OS, which the Steam Deck uses, is Linux-based. It also means that Valve is continuing to further its homegrown software on its own hardware, too. 

Steam OS was launched way back in December 2013 as a way to streamline the user experience purely for gaming. As free software, unlike Windows, it meant having a lightweight and streamlined operating system to get you into games faster. A key advantage of it is how it takes the console experience on PC to the living room, just like the Big Picture mode the client offers. Now the software has taken on a second life on the company's handheld PC line, proving that it can work and be desirable, just not on desktops, it seems. 

It remains to be seen whether the pace can be maintained as more people adopt a Steam Deck into their gaming setups. The Steam Deck is estimated to sell around 3 million units worldwide by