I can't say I quite understand what appeal a Linux gaming PC would have but OK.
Play games on an operating system you can verify most of the code for and compile from source if you need to, for security or modification purposes.
It benefits existing Linux users in that graphics driver support in Linux will improve
Developers should be getting on multiplat engines or use more OS agnostic stuff like OpenGL or SDL anyway. If you're using Unity for example, you can cheaply release a game on Windows and Linux without much issue.