I am actually a big fan of having cure on my hotbar but I half agree with the statement that it is a luxury/supplementary but it is still very useful. I think the main problem is people look Cure by itself and go "Man 200 health... that's tiny." and ignore it. But if you look at Cure taking into account all of GLD/PLD's skills you'll soon see that peasily 200hp can go a long way.

The reason it works is mitigation.

Lets say for some reason you have something hitting you for 500 damage. That 200 hp doesn't seem worth it. But lets say you pop up Shield Oath. Well that 500 damage becomes 400 damage. And your 200 hp cure is still 200 hp. Pop Rampart and that 500 damage becomes 300 damage. Pop Sentinel and that 500 damage is all the way down to 200 damage. Pop both Sentinel and Rampart... well you see where this is going.

With PLD it is not about making your cures big it is about making your enemy's damage small. I've always compared PLD and WAR as a sports car and a family sedan. And in this case if 'heals' were gas, WAR is a bit of a gas guzzler while PLD is much more fuel efficient. So that 200hp really goes a long way if you use it wisely.

If you're taking enough damage to pop one or two of your cooldowns you might as well make the most of the mitigation and toss in a heal or two (if you already have more than enough hate that is.) Also sometimes that small heal is just enough to put you back in your healer's 'safe zone' so where they would take the time to heal you twice they get a free round to play with. I really like how balanced it is, with mitigation its strong enough to be effective but you can't abuse it because you don't want to have 0 MP and then need to flash.

PLD's cure is very much about the finesse of tanking. Sometimes victory is not won by grand efforts but the culmination of very well executed small ones.