Heh, I can understand where you come from. This is weirdly related to life in general. I think you just should use them. They were made for being put on something, it’s their purpose. And they are replaceable. Even if you had some unique ones that you couldn’t just order online again, at some point, you have to let them go, one way or the other. Either forever unseen, stashed away, or gloriously put on the front of something, at least being showcased and allowed to shine for a period of time, while they and the object you put them on are relevant to your life. And even if you “lose” them at some point by letting go of whatever they decorate, there will be other stickers to fill that gap and bring you a different taste of joy. It’s like with people in our lives. Every person, animal or object can only accompany you for a limited amount of time. Some stay longer in your life, some only briefly. Enjoy them to the fullest, while they are there.

If you have some super rare, unique and expensive ones that you’re simply proud of having in your collection, that you get joy out of by simply owning them, it makes sense to collect them without sticking them on something. But let’s be honest, most stickers out there are easy to replace. And you could also go the route of specifically shopping for ones to put on something. ;)