i'm not sure i'd want the myst case hat socket enchantable though. i think it could become potentially broken with the card combo sets.
i mean imagine getting both the merchant and alchemist set cards and having the myst case hat and a second slotted headgear (sunglasses, though i don't know of anyone if very many people having them), you could wear both sets each set boosting mammonite's damage by 20%, plus being a merchant class wearing the myst case hat will also boost your mammonite damage by 20%, throw in a two-hand axe with racial/elemental/size modifiers and you're one-shotting enemies with a level 10 mammo that you've no business one-shotting.