[HowardMei]

But it's not recurring revenue. I can't imagine someone keep buying 10+ packs of stickers. Only stickers, no game credits? There's something I fail to understand here.

[idProQuo]

You simply lack the imagination ;)

People buy the new sticker packs so that they'll have stickers nobody else has. Other people will start getting these new sticker packs, and thus the "trendsetters" need new sticker packs in order to maintain their uniqueness. LINE is happy to keep releasing new stickers to feed this cycle.

[atgm]

Sticker packs come out regularly and some are limited edition. People in Japan are very loyal to their favorite characters, too.