I'm pretty sure they mentioned before that Crysta cannot be redeemed once spend. Which made me opt for a diffirent option. Especially way back when you were unable to deposit exact amounts, but instead had to use 1000's which would always mean you had Crysta left over you essentially wasted ad-infinium.
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[XI] Surivere of Valefor
[XIV] Sir Surian Bedivere of Behemoth
http://na.finalfantasyxiv.com/lodestone/character/2401553/