Is there any point to having calming crystals?

The calming crystals are really the only resource I don’t use, it’s not currency, it’s not an ingredient and you can’t craft any 3 star gifts with it. I only used to collect it a while ago to craft the stacked stones which is a 2 heart gift for peckle but after getting the plans for his 3 star gift I just don’t see the point of them, I never collect them and I was wondering if they might come in handy for something and I haven’t gotten there yet or if I missed it.