Seeing Stelle PVs used to be a good warning sign not to roll a character, but they broke that with Castorice, so it's kinda up in the air. On one hand, they might pull another Black Swan, but it could also just be a cute new waifu. This problem doesn't exist when you get Caelus PVs, since that is 100% just a cute new waifu without the gamble. On one hand, I can get a new Kafka teammate (I don't care about meta), but on the other hand, I risk spending 100 rolls on a character who could get shipbaited because it was a Stelle PV.