I haven’t thought much beyond just being able to conversationally ask a virtual copilot to do various flight related task.
I think it might get kind of complicated to be able to ask for the copilot to load and approach in the nav system or something like that. But something like that would be cool. 
Like get your approach from ATC and then tell the copilot to set and arm the approach.
Basically anything you would find two pilots doing in the real world.