i was wondering about this too. my sis was flying DEN-ATL a few days ago and had breezeway on her bp even though she was on a U fare and was not in an exit row or bulkhead. we got excited thinking it meant she had unknowingly achieved some medallion status through lots of flights to hawaii but turned out she only had 3k mqm and no status.
perhaps delta is teasing people into wanting to achieve status with this breezeway stuff.