Currently there are 3 modes of gameplay you can engage in in OC.
1. Fates/CEs silver grinding.
2. Mob Chaining Gold grinding.
3. And treasure hunting.
Adding currencies to the treasure chests would help solidify it as content worth doing in its own right, as opposed to something that\\'s only done when it\\'s convenient. It also helps to deal with the issue that many people are feeling, which is burnout from either non-stop gold farming or non stop silver by allowing players to search at their own pace.
Diversifying the methods that players can attain currency is a tried and true metric to increase player retention and enjoyment by providing them agency in how they approach the content. XiV is generally pretty good at this(shared fates as an alternative demiatma farm, treasure maps/hunts/roulettes as methods of tomestone farming etc). Adding silver and gold coins of enlightenment to chests would achieve this.
There would still of course still be incentive to engage in gold and Silver currency grinds, by virtue of them granting knowledge and phantom exp, as well as demiatmas from fates/ces. In all likelihood this would be less effecient than 8 man farming good, or even solo farming gold, so it should have minimal negative effect on the current systems, while providing more meaningful methods of engagement within the zone as a whole.
Second and tangentially related, please increase the spawning frequency of the pot fates. This would further add to the "treasure hunting" play style I believe was intended by turning the loop into, chest hunt>pot fate>complete pot>chest hunt.