I am not asking for full video support. I understand that the main focus of Musicbee is the music.
I don't know the implementation details of the tags, but, as I said earlier, I don't see why tagging a video should be any different than tagging a song, and also why the "Video" view (equivalent to the "Album and Tracks" view) should behave any differently.
If there is an implementation limitation, I would love to hear it.