Its only relevant with a midi sequencer engine, really - there isn't one of those yet but the new teensy 3.5/6 makes it possible.
Picking up tempo would be useful for audio effects i suppose, and i can see implementations of lighting effects via Octo's would be very cool too, to augment microphone information. I'm sure there's more potential, but until someone makes drum machine or full sequencer engines and contributes them to the codebase, it's almost a question of why?
If its just tempo and timecode you need ableton will already spit both out via usb-midi, but only as a slave relationship, if i understand correctly.
I think the whole point of link is the multi-master approach for a remote DJ session across the airwaves, it'll keep everyone in sync.