Oh, maybe the real use for gift cards is that the receiver can't haggle. "I know you wanted to give me $200, but how about we make that an even $500 instead?" :)
To clarify about the cashlessness of Sweden: cash still exists, and you can still get government printed bills, but many places have stopped accepting them, and these days whenever someone has non-foreign cash it becomes the topic of discussion: "why the hell do you have those?"
Honestly I don't know that they're useful for anything except donating to homeless(and even they usually have swish these days) or buying illegal drugs
I've never had one, though, so I don't know the specifics.
Apparently, BNP Paribas (one of the major local banks) now has a "teen offer", for people 12-17 yo. This seems to still be attached to the parents' account with the same bank, but the kids get to "manage" the account.
Card payments are not gift cards.