I personally see it as the end of American Dad as a whole, and not some kind of "non-canon" episode like the Simpsons Treehouse of Horror chapters.
It even gives closure to that "golden turd" subplot that has been keep going on for a long time. Also, since the world ended in this episode, so why not making this the actual end of the series? (To make things weirder, this wasn't even the end of the season, which is frankly absurd)
This was the last great American Dad episode, and the series should have concluded here. For me, this is the "true" finale, and I stopped watching from this point onwards. I personally would recommend any other viewer do the same thing.
It even gives closure to that "golden turd" subplot that has been keep going on for a long time. Also, since the world ended in this episode, so why not making this the actual end of the series? (To make things weirder, this wasn't even the end of the season, which is frankly absurd)
This was the last great American Dad episode, and the series should have concluded here. For me, this is the "true" finale, and I stopped watching from this point onwards. I personally would recommend any other viewer do the same thing.