Does anyone knows what the "Soul Leaf" and "Creation Fragment" from the Platinum pack are used for? Can't find anything related to this and when I use one, it tells me

"Do you want to add the card to your collection? Once added, you can find it in your Card Catalog... All cards exceeding the max Enhancement level as well as XP Cards will be converted into XP."

When I do use one, it tells me "Used XP cards and gained 500 XP" but I haven't got XP from it. I'm really lost