In my opinion, Cedex doesnt offer anything interesting. Purchasing diamonds? Therere a lot of other places to carry it out, and you can choose any method from a wide range of them to pay. Moreover, I'm sure that the platform will charge a large commission offering the same prices as the other markets do.
If there will be any commissions, they will be minimum ones. As for the value of diamonds, it will be lower on the platform than on exchanges; consequently, each investor can save money.