i'm using a gift card with the full amount of the phone already on it and i've already uploaded it to my wallet. I purchased something else using the same method and while it adds a good 5-10 seconds, credit card/apple pay is one less thing i have to worry about. While there could also be issues with paying with a gift card, I've had enough credit card transactions randomly decline over the years that I won't take that risk (and no, not insufficient funds, it was always a CC company error that i had no control over).