I've got a site that is totally private. Once you are a member and can login, you can see everything. There are different roles, but they all relate to various administration privileges which can be handled with standard Drupal permissions/roles.
Content Access adds the viewing control, which I don't need on the private side, where everyone can see everything.
I had been using Content Access which seemed like overkill since there was no content that I wanted available on the public site other than a login screen.