There's on part in the recent live letter announcement that shows how important coil story is "Discover what has become of the harbinger of the Seventh Umbral Era in the Final Coil of Bahamut." This is the story of what happened to the destroyer of 1.0, how he went from all powerfull being ripping apart the surface of Eorzea to ending up underground. To me that's a very important part of the overall story. If the story was something like in Crystal Tower which feels like a sidestory, I would have no problem with it, but to me it feels like I'm being left out of the story because I don't raid.

As for people telling others to just watch it on youtube: then why play games at all when you can just watch everything on youtube. It's a stupid answer, people want to have a chance at clearing it themselves and experience the story with their own character.