Haven would like to come up with a IG and IC way to persuade the Merchant to keep them stocked as it would bring revenue into Barovia. And Haven would secure a deal to bring all potions making business done by the Purple Pawns, exclusively to him.
Not to mention this would help Ivory as she has a cauldron in her shop. It still makes all those who dont have shops, go to the Herbalist or Herzzogs... So it doesnt ruin that RP. So it would be nice to see that added, especially since there is no Guilding tanks in town other then private ones, yet there is Vinegar and Mercury in the Trade House.