The reason she would offer a "content exchange" is because a few of these girls actually have the brains to market their own content in addition to just working for other people.
Also, the average porn "producer" is nothing but a jerkoff with a consumer cam and an on-camera flash so doing a content exchange with someone like Holly is a good opportunity.
I do content exchanges with models when I have the time. When they show up on your set and realize you are not just another moron with a handycam they tend to want to work with you over and over.