The community app is only used if there is no game specific application. You must fill out an application for each supported game you want to play. Game leaders decide on their own applications so being a star citizen member does not mean you get automatic membership to PS2.
Once your game app is approved it includes community membership. You do not need to fill out a community app if you fill out a Game Application.
If you just want to play in random gaming groups and hang out as one of us without being tied to a game? Fill out the community application.