Softpedia reports
Steam is the world's largest digital game distribution platform, supporting all major operating systems, including Microsoft Windows, Mac OS X, and GNU/Linux or SteamOS, Valve's own distribution derived from the acclaimed Debian GNU/Linux OS.
[...] There are approximately 6,500 titles in the Steam library. Almost all of them are being supported on the Microsoft Windows platform, a little over 2,300 have support for the Mac OS X operating system, and 1,500 titles offer support for Valve's SteamOS and any other GNU/Linux distribution out there.
[...] Even more good news: [...] Many other games will have support for the Linux platform soon, mainly because Valve will finally release its Steam Machines gaming console / personal computer in November, which will be powered by the company's Debian-based SteamOS GNU/Linux operating system.
(Score: 1, Interesting) by Anonymous Coward on Tuesday September 22 2015, @12:44AM
I still don't use linux for day-to-day stuff. I can give no justification for this, but it's true.
I use both. There is 0 reason not to. I use my OSs to start other programs. That is why it is not important to you. You do the same. But you have others trying to convince you 'only one OS is needed'. I need an OS to start programs. Thats it. If windows runs the programs I use then I use it. If linux/bsd/osx have programs I need, guess what I use?... Do not worry about the 'true believers'. Just keep doing what you are doing. There is no reason for you to feel guilty.