> An upload button alone is no user story, a story might be "As a user, I want to be able to import the Excel reports that I get from company $XY, so that I don't have to manually enter the data, and save a lot of time that way", ideally including a reason why that data needs to be there.

I think that practically this often ends up being "As a user, I would like to have an upload button", Of course, adding "As a user" to the beginning of a sentence does not a user story make.