Here's the really interesting part:
Priority boarding group will only be printed on the boarding pass of the eligible Citi® / AAdvantage® primary credit cardmember. Up to four customers traveling with and listed in the same reservation as the
Citi® / AAdvantage® primary credit cardmember are eligible for priority boarding.
Up until now, priority
boarding for companions has been an unpublished benefit. Now it's published (at least for Citi cardholders) with a limit of four guests.
Edit: Clarified that the card includes priority boarding but not full priority aaccess