Waifupedia

Since the 18th century trading cards have been more or less desired colletibles in our society's. It started with cigarette pictures that came at random with the packages and were ment to drive the sales. Today the closest we have here in europe are stickers with football players that are meant to be collected. They are stickers that are collected in a corresponding sticker album. 

There are also card brands like Magic TG, Pokemon, Yu-gi-oh aso. They are popular and get collected a lot. But they are more collected in a strategic. So its more about speciffic cards rather than getting a set complete. The dive to collect them, at all decreased heavily over tha past years since they play so much better in online than in real life. So usually people buy the card packs just for unlocking their cards online. (not all of course)

Now goddess story cards are pure collectibles. They are pure artworks that don't any instructions for a game on them. (One could invent a game to play with the cards but in my opinion they are too bad to do with that) I would say the cards are a part of the eastern "Idol" mentality. Kind of like our affection for super heroes. The difference is that these "Idols" are fare more in number than any Marvel/DC libery could ever offer. They also don't need superpowers. They are more focused on a specific character attribute. They are also heavy influenced with Anime/Manga. There are real life people but also many Anime characters that count as "Idol".Enough popularity = Idol

Goddess story uses only female Anime/ Waifu characters that are popular in the eastern culture. The cards are made with sophisticated printers and they are really an eye catcher with all their metal/holo and other effects. They come in random packs of around 5 cards with different rarities. So far goddes story released around 20 different sets.