The health/magicka/stamina convenience potions were removed shortly after the Crown Store was released, because they were inadvertently stronger than craftable potions of the same level. We had been informed that the Crown potions would be better than the potions you could purchase with in-game gold, but not better than the ones that you could craft in-game. Once it was brought to ZOS' attention that the potions were not working as intended, they removed them. I imagine they'll return once the kinks are worked out.

Save your crowns for the XP potion, you cannot craft that.