I had two from my own missions, bought two cause I was impatient. If I didn't care about getting the mount I would probably just buy enough to hit exalted and save them for DMF, yeah, but since I need to grind that apexis anyway... Only advantages past revered are the boat contract the infinite augment rune. But spending 100k+ just to get the rune a few days faster is irrelevant when I could spend a fraction of that on the consumable runes for all the mythic/big heroic pulls between now and exalted (which at 5340/21000 revered will only be ~2 weeks)