To answer the primary question, the purpose of all stories is to entertain.
The idea that the stories should also "count" and/or "matter" to the ongoing narrative is a peculiar part of comic book fandom, and not something I understand. I prefer to be entertained first and foremost, not worry about how each story is going to affect the larger universe. Otherwise, it's a little bit like putting the cart before the horse, and that's how you end up with Flash Rebirth and the secret origin of Barry Allen's bowtie.
If there's a story I didn't like, no problem, it's not part of my personal continuity.
Fans like to take the puzzle pieces that serve as 50 years worth of stories produced by hundreds of different people, and then fit them all into the same puzzle perfectly, and they are never, ever going to do that.