Although I have- you really don’t need to. It’s pretty cool, plus I love the stickers!
Though recently- not sure if a bug or just me- I haven’t been able to buy stickers. When I click on something, say, Steven Universe, it shows nothing and tells me to come back soon. I click on sets and stickers and try from there, still nothing.
Hopefully nothing happened to my account and it’s just a bug, and hopefully it’s fixed soon so I can buy more stickers!
Cyphorium about Quidd: Digital Collectibles, v1.10.5