The difference being, you are a BLM, so your team will always have it. Sleep and Weight are two of the only status effects that last longer than 12 seconds, and even really call for the reduced cooldown on Purify. You can sit through a few stuns, that have diminishing returns, and live. Then you get to run free for a whole minute immune to stuns. If you get Swiftcast Sleeped, Purify out of it, and get put to sleep again, you're still asleep for 15 seconds. Not to mention the instant cast AoE sleep that BLM can take as a PvP skill. 15 more seconds of sleep, on the enemy group, without sucking up your Swiftcast, and the next sleep is still 15 seconds. Try all you want to defend it, but it doesn't matter if it can be on both sides of the fight, it's still broken. Crowd control abilities that can turn a 4v4 into a 4v1 for nearly a minute should not go unchecked.