The first Witches Festival introduced a crown store exclusive motif, The Grim Harlequin, for 2200 crowns and includes 54 crown mimic stones.
The cause of the issue relates to a shift introduced with OneTamriel that focuses crafting to individual characters. For example, harvesting is now determined by the harvester’s adventuring level and crafting passives. For harvesters-for-profit and mat-provided crafters who wish to continue to do so need f a variety of levels or crafting passives in order to stock up on mats of all tiers.
The issue with the new paradigm is that if you don’t have the exclusive motif, you will have to rely on someone else to use their crown mimic stones to create the item for you or deconstruct a item created with a crown mimic stone to obtain a sell-able style item used to create it. Overall, it seems poorly thought-out from an in-game economy perspective.