1. This would allow playback speed of a video to be 'set' like a sample at a specific BPM.
If you sync them, you could adjust the video to playback faster or slower to match the music.
I don't know how much experience you have with other products, but in motion dive.tokyo you could bring in MIDI Beat Clock and use that to speed up or slow down the video playback in sync with the music. This would likely be similar, only without the external source - it would be internal based on the speed of the music.
3. Random on beat would mean applying an effect or other change on the beat, but the effect or change would be random in nature.