It's not 100 a day, but actually you could get up to 500 Blossoms an hour, and if you dual client, its 1000 blossoms and hour. Also, the blossoms can be traded through legion warehouse but cannot be tradeable through account warehouse. Why is it like that? Did the Dev mess up or was this intentional? Yes, most people will end up with 20+ ancient contracts if not more by the end of this event. There is only a few fix to this.
1.) Take away the Pure Aether Blossoms or reduce the amount it gives.
2.) Make the Blossoms untradeable through Legion Warehouse.