Dont Spoil Things
My guess is that if the b-day present could be a random pick from say 12 mini’s and the remaining 30 from the gem store but they were all labeled as being of the same set (yes completionists, a set) then they might’ve even gotten more people interested in getting more of them. For that to work the mini’s should be tradeable of course.
It’s a game forum. The truth is not to be found here.