I’ve seen quite a few people wondering what the point of SteamOS is and why you would want it.
It simply boils down to uncoupling PC gaming from its reliance on Microsoft. At the moment the PC gaming market is dependent on Windows, DirectX and more recently Xinput for controllers. Each of these places constraints on the experience for the end user which SteamOS aims to lift.
Consoles are generally considered to have better performance given their hardware compared to PCs. This is due to fewer overheads and developers being able to coded closer to the metal. DirectX is starting to look rather constrained , dated and as a result there is a move towards alternatives such as AMD’s Mantle API which work at a lower level and better leverage the parallel nature of modern technology. If Valve’s promises are realised gamers who typically spend large amounts of money to suck out every last frame rate improvement should get better performance than they would on Windows.
Since its introduction alongside the Xbox 360 XInput has standardised controller input for PC games. This has been somewhat of a double edged sword as although it makes it using an Xbox 360 controller seamless on a PC it makes any other controller a step more difficult to use. For example to use a generic controller on Sonic & All-Star Racing Transformed you need to either use an Xbox controller emulator in the background or edit config files for each and every game.
If you build a new PC you currently have to factor in the cost of a Windows licence, with SteamOS you just need the hardware. As more developers migrate away from Windows towards SteamOS it also opens up the doors for more Linux distributions and Mac OSX to become mainstream players rather than side attractions.
A typical user either doesn’t want to bother with the maintenance and complexity involved in Windows PC gaming. SteamOS promises are simpler out of the box experience which just works out of the box and requires less knowledge by the user.
Each of the aspects of Valve’s ambition require a long slow push to move the direction of the industry which should eventually be beneficial to everyone.