I think this is a crucial feature for any consultant - copy a recorded talktrack (for example explainer video) from one board to another. 

Yes indeed, but I guess that use case is not thought of. I have a concrete one, where I provide small knowledge bites on a weekly base. I have one board as master version where I prepare the content and then copy it over into the public board. With the great new feature where content can be copied via reference instead of a real copy, I can modify content on the master which is automatically updated in the public version. BUT: Any talkback I have to do on the public version, as I can’t copy that one from one board to the other. ;(