You really don't need gift cards, anymore. This is a cage with the doors left unlocked.
And as much as we love to blame the publishers, geographic restrictions are being imposed by authors (they sign with different publishers for different regions rather than giving one publisher worldwide rights). Assigning worldwide rights for English language editions would make more sense for the consumer, yes. But then US stores would have to start collecting EU VAT, for example. The devil is in the details, and it is a lot easier if they just leave the backdoor open.