While others may scoff, I think this is an accessory that would be very welcome to anyone that makes a habit of straight tanking.
While potentially losing out on a bit of overall damage or accuracy, a SAM, WAR, or PLD that is blood tanking wearing this will survive at least a little bit longer.
And with the change to Cure Potency that allows Cure/Waltz recieved to be independent of Caster's 50% Cure+ cap, I see this taking at least a little jump in price.
With the change to cure potency, this earring will effectively give you a 7.5% boost to cures when stacked on top of a mage's 150% cure spells. Pretty awesome.
It says received so guessing it's cures ppl cast on you. So can be useful for helping a WHM keeping you cured. And maybe lets you break the +50% potency cap~!