I help with the Chesapeake Regional and for the past 5 years have trained Student Ambassadors. There is always a lot of overlap between the Student Ambassadors and team members who do the RCA presentations. Each regional is different but the experience as an ambassador talking to the public and the VIP's is similar to doing a RCA presentation (except you are usually walking while talking.
) Enthusiasm and being able to talk about your team and what they accomplished, along with talking about the big picture of FIRST are all important. But would not be showing your video.
You might inquire whether your regional has such a program and if so, volunteer your RCA presenters for this role!
RE: video. Your video can come in handy for next season for sponsorship and outreach.