That's the whole problem, it makes so many non "meaningfull" content useless. Fates, Mandates, gear progression, side quest (included side dungeons), anything Grand company related, gear progression... Everything is made useless by the unsane amount of xp you get. You may find them useless content, but I feel having to engage with them is part of what made the world works so well in ARR, despite the the msq and storytelling being a little harsh. They give the whole world some consistency, made the world feel alive. It's something we lost with time and that was severely lacking in DT. As much as people like to describe it as the new ARR, ARR did a far better job at fleshing its world, and those side activities played a big role in that. One of the current complaints about the game is how the world is shallow and just a setting for the msq. Of course it is, they made a point to make anything not msq related useless and inconsequencial. No wonder people tell ARR is the bad part of FFXIV if they experience it only through msq.
Once again, I don't want them to reduce the xp for everything, but to give us a tool like Menphina or Azeyma earrings, but that cut xp instead of giving more. You don't see the interest, fine. I see it though.