Based on what moderators have posted on the Gladiator thread, this is your last opportunity to make use of Leviathan pearls. I think you can fairly assume they can only be used for this purpose. TL is awarding Leviathan pearls alongside morningstars for a limited time. That alone should warn you that the pearls have no other/future value.
I suggest you craft the extra Leviathan now and trade it out for large gems if you don't want the dragon.