Honestly, I am pretty sure it wouldn't crash the economy since there are tons of methods of making gil. Alexs and relic currencies surely didn't so I know this wouldn't. Plus SE can always make it where you can exchange 1 CV for 1 HMP or 5 for 1 Riftdross/Riftcinder for the purpose of balance. As much as I hate to have suggested that and hoping for 1 for 1, this seems like a realistic and balanced suggestion that should be consider. The only objection I can foresee is if they do it for this, then they have to do it for relic currencies, alexs, and HPB (even though you can exchange bayld for HPB already).