Well, there's a lot of objects in game that should be 'stickable' but aren't. For example quickterms, liteterms and any of the workshops used for production of fine candy. Although you can label with a spraypaint if you want, it might not look as good as sticker would. Briefcases and similar allowing sticker woulds be good.
But on other hand, I'm positively sure stickers are more in the game for customizing items more to your personal liking than just labeling, their price and how you make them suggests that too.
I would definitely like stickers working on a lot of new objects for role-playing opportunities, including sticking an object to be your favorite and then losing them! Great RP to get that object back will happen!