I don't know much about how other VJs are using Rekordbox (if at all) but I use both audio and music video interchangeably during a set; if I don't have the video, I play audio-only with the fallback video loop mechanism that's built-in.
What pisses me off most is having to look in two different places depending on the media type. I'd much rather see all tracks, regardless of format, in the one playlist.
Video certainly doesn't even have equal weighting in Rekordbox;
– you can't put a video playlist into the Playlist Palette
– you can't make shortcuts to video playlists
– The playlist pane is specifically for audio, and not video
Pioneer have made a point of introducing video functionality into their product line-up, yet make it so difficult / restricted for users to manage their library in a way that suits them? I can't see any reason to prevent someone making mixed playlists. It's just making my job harder.
Admittedly, I'm having to carry on using Virtual DJ (urgh!) until such time that Pioneer up their game in terms of software, especially on the video integration front :-(