We are going on vacation this summer to the foreign land of Canada, to see the two-dollar coin. We realized that we now need passports, all 5 of us, to get across this heavily fortified border. So now they have a passport card, which is not good for air travel. IT costs a bit less, but..., well it's not good for air travel, and we might go to Scotland sometime in the next few years. Question is, is there any reason to go with the passport card when one is going between US and Canada?