I thought she's in both versions? I know I have a "press release" one that doesn't have the chorus or Mike saying "It's going down. It's. Going. Down" at the beggining but the radio edit version does. I think it's somewhat of a demo. It seems unpolished and unfinished.
Promos can sometimes be considered advanced versions of stuff. Advanced meaning not the 100% final product. It is/was a promo.
I read an interview about the making of the video, and Brad was talking about how excited they were to be doing the song, so I guess they wanted everyone to hear it, before it was done.