If I get it correctly, there’s only the ability to show exactly one kind of rating.
Standard is to show imdb ratings. If I check “use user rating” in settings, only user ratings are shown, no imdb ratings anymore. And when I check mpaa ratings, neither user ratings nor imdb ratings are shown.
I rate movies with my own user rating after I watched them. So would it be possible to show both: imdb ratings and user rating (if available)?
Well not really 
I can show all ratings in the info view, but not in the lists and when you sort by rating you need to know what rating, it can’t be both too.
Having all ratings in the info view would be cool.
For list view I would suggest to prioritize the user rating if existant
Priorise is not logical 
How would you know what kind of rating is displaying, when sorting on both it would have 0 meaning for user.
I guess the user knows if he has rated a movie or not. If he forgot, he would be able to see in info view, if all ratings are available there?
Nice taste of music 
He can’t remember all, in a list of 500 movies ordered by ratings, you can’t know if the movie rated 8 is 8 because of IMDB or you. That makes the ordering completely random for the user since if he want to have 2 different rating system it’s because the 2 system have different values or meaning to him. Mixing them does not makes that 2 times better, just a mix of apples and oranges and that can’t work.
And the video is more about Highlander “There can only be one” 
Old classic
Next version will show both types of ratings in info dialogs / activities.
You’ll sill only have one main rating used in lists and for ordering.