I come from the background of the old-style leveling parties of FFXI, where players just sat in one place for hours on end pulling mobs that you fought in order to get EXP. Occasionally you would stop to let the healer rest to get MP back (or not if there was a BRD in the party with Mage's Ballad), but for the most part it was hour upon hour of just sitting in one camp, farming the same mobs, and once you got past a certain level, you'd move to another camp and do the same thing.

For me, running FATEs and dungeons for EXP is a significant improvement over the EXP parties of the past that I had participated in for two very important reasons. 1) You're not sitting in the same place doing the same thing. Sure, the tasks you do may be repetitious, but you're always on the move to that next area and the tasks you perform in order to get the gold rank change so you're not always doing the same thing. 2) Income. While it may not feel like a whole lot (and it probably isn't, since XIV has a notable issue with the amount of new money coming into the system), you ARE getting significantly more income in the form of Gil and Free Company Seals than you would be just farming monsters. On top of that, running dungeons appropriate to your level while running FATEs gives you the chance at really good gear that could last you a significant amount of time, again not something you would get if you just farmed monsters.

It's not a perfect system, as the income could be better and I'd like to see a slight boost to dungeon EXP, but I consider it a massive improvement over the old EXP party.