The extension’s primary uses are in preventing the game window from freezing while being dragged around and being able to have borderless fullscreen.
Neither are an issue on Mac and Linux - it’s safe to drag the window and there are no quirks that would require having two kinds of fullscreen.
And if you’d like to dynamically toggle the window border on Mac (window_set_showborder doesn’t seem to work on Mac yet? I think?), Samuel made an extension for that (BorderToggler).