I was hoping Bitrefill would add the difference to my account when I paid more than needed for a gift card, but unfortunately they didn't. I tested it with a small amount, so it's not worth complaining about, but it would be a great feature (to avoid small change outputs) if I can pay any amount I want. I could do this by using "Top-up Balance" first, but paying directly is faster to buy something.
It's been months since bitrefill was active here, so no rush