The launch options don't do anything to your computer unless it runs the game in realtime, which it is not. Launch options are only for changing how the game launches, hence the name.
Actually, the launch options in this thread forced Rust to run in weird DirectX sublevels, which glitched out the renderer and in some cases provided incredible FPS boosts (3x sometimes, on marginal systems, putting them over 50fps) at the expense of the sky totally freaking out with a Hall of Mirrors void effect unless you also enabled vsync or something.
These were always unsupported. Then garry just broke being able to use them, so they don't have any effect on Rust. That happened in the five months this thread has been collecting dust before Xecnorex decided to register just to necrobump it.
Xecnorex, type "gfx.all false" into the Rust F1 console.