The Source, Metro's award-winning blog, has a post you should read entiled: The Crenshaw/LAX Line final environmental document has been released
Yes, this matters to you who live, work and play north of the Expo Line.
The best chance to connect West Hollywood and mid-city Los Angeles to Metrorail currently seems to me to be as part of a northern extension of the Crenshaw/LAX line which has as its initial northern terminus as the Expo Line, likely to be extended to Hollywood/Highland in the future, and quite possibly via West Hollywood (as San Vicente and Santa Monica both has rail service for decades).
Metro Study to extend Crenshaw/LAX Line
While this would not have provide a one-seat rail ride to the beach as studied for the West Hollywood transit corridor as part of the Westside Subway Extension project, it would provide a one-seat ride to/from LAX, which is more than a even trade in my opinion.
So yes, this project matters to you if you live north of Crenshaw and Exposition.