Crediting artists in music video as themselves or an acting gig.
I have added several music videos in the past for some associates of mine. Something that seems to get under the artists skin. Is when someone credits them as actors instead of self.
While it is possible for a musician to play a role that is not himself and perform his music, then it's different. That's a clear acting role.
It is also possible that an artist to have some dialogue with an actor in the music video. What comes to mind first is Ben Stiller having a dialogue with Puff Daddy and Limp Biskit in their music video. Now there is ambiguity.
However if the artist performs his song even in a set up it's a self-credit, in my opinion. For example Madonna -Die another day. She is credited as Madonna playing herself, no it's the real Madonna performing a song.
I took this video because there is acting coming from her, she needs to pretend to be a prisoner. But it is still a Self credit in my opinion. It's not because a song is a performance that it qualifies as acting.